IB+DP+Topic+2+Mechanics


 * [[image:engeering failure.PNG]] || [[image:spacex.gif width="559" height="333"]] ||
 * Image from www.brsresults.com || Image from http://bgr.com/2017/09/14/spacex-launch-failure-video-explosion/ ||

2.1 Motion **//Essential idea//**: Motion may be described and analysed by the use of graphs and equations.

//** Nature of science: **// Observations: The ideas of motion are fundamental to many areas of physics, providing a link to the consideration of forces and their implication. The kinematic equations for uniform acceleration were developed through careful observations of the natural world. (1.8)

//** Understandings: **// • distace and displacement • Speed and velocity • Accleration • Graphs describing motion • Equations of motion for uniform acceleration • Projectile motion • Fluid resistance and terminal speed

• Determining instantaneous and average values for velocity, speed and acceleration • Solving problems using equations of motion for uniform acceleration • Sketching and interpreting motion graphs • Determing the acceleration of free-fall experimentally • Analysing projectile motion including the resolution of vertical horizontal components of acceleration, velocity and displacement • Qualitatively describing the effect of fluid resistance on falling objects or projectiles, including reaching terminal speed
 * // Applications and skills: //**

//** Aims: **// • Aim 2: much of the development of classical physics has been built on the advances in kinematics • Aim 6: experiments, including use of data logging, could include (but are not limited to): determination of g, estimating speed using travel timetables, analysing projectile motion, and investigating motion through a fluid • Aim 7: technology has allowed for more accurate and precise measurements of motion, including video analysis of real-life projectiles and modelling/simulations of terminal velocity

//** Data booklet reference: **// =Kinematics= [|Distance Time graph] from absorblearning.com [|Kinematics notes] from ibguides.com

To investigate the difference between constant velocity and acceleration using a ticker timer
Create displacement-time and velocity-time graph from your own measurements for different kinds of motion. 1. Cut the tape through the dot (or set of overprinted dots) produced just before the object was released. 2. Count ten dot-to-dot spaces and cut the tape again. (If the dots are too close together to distinguish them, then you will have to estimate the ten spaces.) 3. Starting from your last cut, count ten more spaces, and cut again. 4. Repeat this, until you have a collection of consecutive tapes, each one longer than the one before it. (Number the order of your tapes, from 1 onwards). 5. Draw a horizontal line on a sheet of paper. Make a 'bar chart' by sticking the tapes vertically side by side, so that their bottoms just touch the horizontal line. The first and shortest tape should be at the left hand end of the line.

Graphs
Physicslab.org [|Constant velocity] vs [|Constant acceleration] Hyperphysics.phy-astr.gsu.edu [|Graphs of motion] and [|Problems] from The Physics Hypertextbook [|Recap of motion graphs] from Hyperphysics.phy-astr.gsu.edu

Uniform acceleration (= constant acceleration): Uniform acceleration occurs when the velocity of object changes at a constant rate.

Falling through the air
media type="youtube" key="E43-CfukEgs" width="560" height="315" BBC TWO [|Brian cox visits the world largest vacuum chamber] from youtube.com

Identify the acceleration of a body falling in a vacuum near the Earth's surface with the acceleration g of free fall.
When we ignore the effect of air resistance on an object falling down to earth due to gravity we say the object is in free fall. Free fall is an example of uniformly accelerated motion as the only force acting on the object is that of gravity.

On the earths surface, the acceleration of an object in free fall is about 9.81 ms -2.

Describe the effects of air resistance on falling objects.
Air resistance eventually affects all objects that are in motion. Due to the effect of air resistance objects can reach terminal velocity. This is a point by which the velocity remains constant and acceleration is zero.

In the absence of air resistance all objects have the same acceleration irrespective of its mass

=Terminal velocity= **Task:** 1. Draw free-body diagrams showing the resultant force of each step until a falling parachutist in the animation reaches at the terminal velocity. Skydiving media type="youtube" key="ur40O6nQHsw" width="448" height="251" [|Physics of Skydiving] from youtube.com 2. Plot a velocity against time graph of a falling parachutist in the animation and explain what the terminal velocity is. ( __**Graph**__ of terminal velocity during a parachute jump from absorblearning.com)

=Projectile motion=

**Projectile** Any object that is given an initial velocity and then follows a path determined entirely by gravitational acceleration. Projectiles follow a predictable parabolic path. Once forced into motion the projectile is only acted on by gravity, ignoring any impacts of air resistance.

//____ // media type="custom" key="28512493"

How can you make your cannon ball travelled further away from the starting point? Discuss and list the ways with your partner. 1 2 3 4

//**Projectile motion**// //**A predictable path traveled by an object that is influenced only by the initial launch speed, launch angle and the acceleration due to gravity.**// media type="youtube" key="zMF4CD7i3hg" width="504" height="283" Shoot and drop from youtube.com: Watch the ball drops at 1:07 frame

Projectile Motion Notes and practice questions

[|Projectile Motion Teacher Toolkits] from physicsclassroom.com [|Topic 2 Kinematics keywords quizlet]

Projectile Motion II
Parabolic motion is polynomial regression of degree two. This means you are looking for a quadratic equation to define the motion. In groups of three, throw a ball to each other that follows a smooth symmetric part whilst the third person is filming. You have to measure the distance and height of the ball from the thrower at regular time intervals. These values need to be entered into an Excel document and a scatter plot should be produced. On that scatter graph, you need to apply the quadratic regression to find the curve of best fit and any differences between the data points and the quadratic equation generated need to be explained. REGRESSION: a measure of the relation between the mean value of one variable (e.g., output) and corresponding values of other variables. [|Projectile motion] from methacton.org Acceleration due to gravity lab from hpsolomoka.wikispaces.com Acceleration due to gravity key ideas sample lab report

What would be the optimal angle of the golf ball that makes the furthest distance? What do you experience with the projectile motion when playing golf on Earth? [|Alan Shepard playing golf on the moon] Image from imperialearth.com A ball is thrown upward with a initial velocity of 19.6 m/s. Plot displacement-time, velocity-time and acceleration-time graphs of the ball for 4 seconds. Use the gravitational field strength as -9.8m/s 2.



**Research tasks:**
Find the 3 most important applications of Kinematics in the real world. (One example: Uniform acceleration under the standard celestial conditions of Earth) You must justify: 1. Why these are the most important. 2. Explain how they relate to everyday life. This activity is to be completed in groups of 3 or 4. 30 minutes to research your application 15 minutes to prepare the presentation Each of the groups will have 3 minutes to present their findings.

The effectiveness of your presentation will be judged by the other groups according to the criteria of importance, accuracy, interests of audience, correct use of terminology and notation.

[|Projectile motion Hotel jumper crime scene] Aplusphysics.com [|Additional crime scenes for projectile motion unit]

media type="youtube" key="HKxxfKww0UY" width="560" height="315" Top 10 mist insane drag wheelstands from Youtube.com media type="youtube" key="6dh-U-MIgS0" width="560" height="315" Fastest ever street legal 1/4 mile drag week 2015 from Youtube.com [|KHANAcademy One Dimensional Motion]

1.__Acceleration (**a**)__: this is the change in velocity per unit time, or how fast the velocity is changing. This is a vector quantity and usually represented in meters per second per second, m/s/s.
 * Keywords**

2.__Acceleration due to gravity (**g**)__: this is a constant g. On Earth g=9.81m/s/s.

3.__Distance:__ this is the overall length of the path travelled. This is a scalar quantity.

​4.__Displacement__: This is the magnitude of the difference between initial and final positions, the shortest distance between the two positions. This is a vector quantity.

5.__Speed(S)__: this is the change in position per unit time. This is a scalar quantity and is usually represented in m/s.

​6.__Velocity (**v**)__: this is the speed and direction of an object. This is a vector quantity and is usually represented in m/s with some directional coordinate or by a bold letter.

​7.__Horizontal__: this is the direction at which the gradient of the gravity at a point is perpendicular, in other words the direction parallel to the ground and perpendicular to the direction of gravity.

​8.__Vertical__: the direction which is aligned with the gradient of the gravity field, rather the direction which is aligned with the direction of gravity.

9.__Kinematics__: the study of objects in motion.

10.__Origin__: the crossing/intersection of the x-axis with the y-axis.

11.__Range__: This is the magnitude of the x-displacement of the projectile trajectory.

12.__Two- Dimensional__: This means two independent directions of motion. For example horizontal and vertical motion or x and y motion.

13.__Scalar__: a quantity which is described by a number and unit.

​14.__Vector__: a quantity which is described by a number and a direction. A vector is represented in print by a bold italicized symbol, for example, // **F** //.

15.__Launch Angle__: this is the angle above horizontal from which the steel ball is launched out of the launcher.

16.__X-direction__: the direction parallel to the horizontal direction and perpendicular to the y-direction.

17.__Y-direction__: in this case the direction parallel to the vertical direction and perpendicular to the x-direction.​

18.__Component__: this refers to the projection of a vector along either the x-axis or y-axis. Usually this corresponds to x-component of a vector F being labeled as Fx. Fx in most cases is defined as Fx=F*cos(angle), where cos is just cosine. Similarly with the y component, Fy=F*sin(angle).

19. Trajectory: The pathway that an object follows. media type="youtube" key="DY3LYQv22qY" width="560" height="315" MIT Physics Demo -- Center of Mass Trajectory [|mittechtv] Uploaded on 31 Mar 2009

• v = u + at • s = ut + (1/2) at 2 • v 2 = u 2 + 2as • s = 1/2 (u + v) t

2.2 Forces //** Nature of science: **// Using mathematics: Isaac Newton provided the basis for much of our understanding of forces and motion by formalizing the previous work of scientists through the application of mathematics by inventing calculus to assist with this. (2.4) Intuition: The tale of the falling apple describes simply one of the many flashes of intuition that went into the publication of Philosophiæ Naturalis Principia Mathematica in 1687. (1.5)

• Objects as point particles • Free-body diagrams • Translational equilibrium • Newton's laws of motion • Solid friction
 * // Understandings: //**

• Representing forces as vectors • Sketching and interpreting free-body diagrams • Describing the consequences of Newton's first law for translational equilibrium • Using Newton's second law quantitatively and qualitatively • Identifying force pairs in the context of Newton's third law • Solving problems involving forces and determining resultant force • Describing solid friction (static and dynamic) by coefficients of friction
 * // Applications and skills: //**

• **Aims 2 and 3:** Newton’s work is often described by the quote from a letter he wrote to his rival, Robert Hooke, 11 years before the publication of Philosophiæ Naturalis Principia Mathematica, which states: “What Descartes did was a good step. You have added much several ways, and especially in taking the colours of thin plates into philosophical consideration. If I have seen a little further it is by standing on the shoulders of Giants.” It should be remembered that this quote is also inspired, this time by writers who had been using versions of it for at least 500 years before Newton’s time. • **Aim 6:** experiments could include (but are not limited to): verification of Newton’s second law; investigating forces in equilibrium; determination of the effects of friction
 * // Aims: //**

//** Data booklet reference: **// • F = ma • F f __<__ μ s R • F f __<__ μ d R

State Newton’s first law of motion. NEWTON’S FIRST LAW OF MOTION: A body continues to maintain its state of rest or of uniform motion in a straight line unless acted upon by an external unbalanced force.

Examples of Newton’s first law. <span style="background-color: #ffffff; font-family: Arial,Helvetica,sans-serif;">INERTIA: The property of matter which makes it resist acceleration. media type="youtube" key="OEmezNJQCOk" width="448" height="251" Shopping cart disaster from youtube.com

Condition for translational equilibrium. <span style="background-color: #ffffff; font-family: Arial,Helvetica,sans-serif; font-size: 12px;">TRANSLATIONAL EQUILIBRIUM: When the net force on an object is zero in all directions (ie no linear acceleration). Newton's first law of motion for translational equilibrium can be described that an object will remain in translational equilibrium unless a resultant force acts on it. Resultant force in different situations. Newton’s second law of motion. One newton (N) is defined as of a resultant force, which accelerates 1 kg of an object by 1 m/s 2. Acceleration is proportional to resultant force, for a constant mass, and inversely proportional to mass, for a constant force. Students should be familiar with the law expressed as: F = ma and F = Δp/Δt

<span style="background-color: #ffffff; font-family: Arial,Helvetica,sans-serif; font-size: 12px;">NEWTON’S SECOND LAW OF MOTION: ∑F = ma The rate of change of momentum of an object is proportional to the applied force and takes place in the direction in which the force acts.

Solve problems involving Newton’s second law. What is F 2 applied to m 2 ? What is F 2 applied to m 1 ? [|Force on two masses] from hyperphysics.phy-astr.gsu.edu/

Newton’s third law of motion. NEWTON’S THIRD LAW OF MOTION: Whenever a particle A exerts a force on another particle B, B simultaneously exerts a force on A with the same magnitude in the opposite direction. media type="youtube" key="3k_TagfAJFY" width="560" height="315" MIT Physics Demo -- Fire Extinguisher on a Tricycle [|mittechtv] Published on 31 Mar 2009

Examples of Newton’s third law. Students should understand that when two bodies A and B interact, the force that A exerts on B is equal and opposite to the force that B exerts on A. Balloon, Hero's engine, Coke with Mentos car, Believe it or not "[|Coke jet pack]" from youtube.com

Example Q) 18. A 500 gram ball lying on the ground is kicked with a force of 250 N. If the kick lasted 0.020 seconds, the ball flew off with a speed of ___ m/s. [|Glenbrook 163 question]s from www.mwit.ac.th

Example Q) A 250g bullet is shot out of a rifle with a barrel length of 79 cm. If the gun power is capable of applying an average of 32,000 N of force to the bullet over the length of the barrel, what is the muzzle velocity of the rifle? Questions and answers are from[| Mr Burch's class]

Example Q) Example 3: A car that weighs 14700N is traveling along a straight road at a speed of 108 km/h**.** The driver sees a deer on the road and has to bring the car to stop in a distance of 90**.**m. Determine (a) the necessary deceleration, (b) the stopping force, (c) the brakes force, if the road friction is 2100N, and (d) the stopping time**.** Try to solve the problem yourself before looking at the solution**.** Vi = (108 km/h ) (1000m / 1km) ( 1h / 3600s) = 30.m/s (Use horizontal fraction bars only) (a) Vf2 - Vi2 = 2 a x ; (0) 2 - (30.)2 = 2 (a) (90.0m) ; -900 = 180a ; a = - 5.0 m/s2 (deceleration).  (b) ΣF = Ma ; ΣF = (1500kg)(- 5.0 m/s2 ) = -7500N  (c) ΣF = Fbrakes + Ffriction ; -7500N = Fbrakes - 2100N ; Fbrakes = - 5400N.  (d) a = (Vf - Vi) / t ; t = (Vf - Vi) / a ; t = (0 - 30.m/s) / (-5.0m/s2) ; t = 6.0 seconds [|Solution] from www.pstcc.edu [|Newton's three laws of motion] from youtube.com media type="youtube" key="iH48Lc7wq0U" width="448" height="251"
 * Solution:** The mass of the car and its velocity in (m/s) must be determined first. Recall that w = Mg. The mass of the car is therefore, M = w/g, or M = (14700N) / (9.8 m/s2), or M = 1500kg.

[|Newton's cradle ball tricks] from youtube.com media type="youtube" key="JadO3RuOJGU" width="448" height="251"

WEIGHT - The force of gravity on a body. W = mg, where W is weight in Newtons. N; m is mass in Kilograms. kg; g is gravitational field strength in Nkg -1. On Earth, g = 9.81 Nkg -1 Each force should be labelled by name or given a commonly accepted symbol. Vectors should have lengths approximately proportional to their magnitudes.

Free-body diagrams representing the forces acting. FREE-BODY DIAGRAM: Shows all of the forces acting ON an object. <span style="background-color: #ffffff; background-image: url(">[|Construction of free body diagram activity] from www.wisc-online.com
 * 1) its weight acting vertically from the centre of mass
 * 2) all forces where it is contact with other objects
 * 3) any magnetic or electrostatic forces

An object is in translational equilibrium when the sum of all the external forces acting on the object equals zero. This also means an object is in translational equilibrium when it is experiencing zero overall acceleration. Therefore, it is either not moving, or moving at a __ constant __ velocity.

Newton's first law of motion: An object will remain at rest (for an object in stationary motion) or continue to move in a straight line at a constant speed (for an object in constant motion) unless a resultant force actis on it. An object is in __ translational equilibrium __ if there is no acceleration or a resultant force acts on it.

Any object in translational equilibrium will have one or more pairs of equal and opposite forces acting on it. Such pairs of forces cannot be 'Force pairs' in Newtons third law. (Newton's third law: There is reaction force, from a second body, with the same magnitude but in the opposite direction, to the first body, whenever there is a force exerting from one body to another. These DO NOT act on one object).

Example Q) An elevator accelerates upwards at 1.2 m/s. What is apparent weight of a 65 kg person riding the elevator? Questions and answers are from<span style="background-image: url(">[| Mr Burch's class]

NORMAL REACTION: Two objects in contact each exert a force on the other which is perpendicular to the surface. TENSION: A force produced in a body when opposing forces are stretching it. The opposite is a compression force when two forces are squashing a body. UPTHRUST: An upward force on a body which is immersed in a fluid (liquid or gas). LIFT: An upward force on the wing of an aircraft due to the air flowing around it.

FRICTION ( F f ): The force which opposes motion when one surface moves over another. It is caused by the roughness of the surfaces. μN= F f = Frictional Force (N) μ (mu) = coefficient of friction (different for every object - larger coefficient = rougher surface) N = Normal Force (N)

where: N = mg (flat surfaces) N = mgcosΘ (inclined planes)

There are 2 types of friction: 1)Static (F S ) friction - when the two objects are stationary. 2)Dynamic (F D ) / Kinetic friction - when one or both objects are in motion

Example Q) A force of 300 N causes a 50 kg box to start to move, but a 250 N force keeps the box moving at a constant speed. What is the coefficients of static and kinetic friction between the box and the floor ? Answers from [|Ms. Taylor's Physics] media type="custom" key="28753458" Coefficient of friction is the ratio of the frictional resistance force to the [|normal force] which presses the surfaces together. There is a significant difference between the coefficients of [|static friction] and [|kinetic friction].

[|Image from Hyperphysics]

Example Q) A 100kg rock is accelerating down along a hill at 5 m/s 2 . Calculate the coefficient of kinetic friction when the angle of the slope of the hill is 45 o.

Example Q) A 45 kg box is sitting on a 30 degree incline. What is the coefficient of static friction between the box and the incline? If the coefficient of kinetic friction is 80% of the coefficient of static friction, how much mass must be removed from the box in order to begin sliding down the ramp at a constant speed? With what acceleration would the box slide down the ramp? Answers from [|Ms. Taylor's Physics]

[|More practice questions on friction] from Tuhsphysics, [|physicsguru.in] , and [|Physics.oregonstate.edu] 1.__Force (**F**)__: this is the outside influence which causes a mass to change its direction, acceleration, or shape. In this case, direction and acceleration. This is a vector quantity and usually represented in Newtons, which is a kilogram-meter per second per second, N=kg*m/s/s.
 * Keywords**

​2.__Gravitational Force (**F**g)__: This is the force exerted by the mass of one object on the mass of another object where both objects are separated by a certain distance, in this case the Earth on the steel ball. This is a vector quantity.

3.__Gravity__: the phenomenon by which all objects with mass are attracted to one another, this is what gives objects with mass weight.

​4.__Mass__: a quantity which represents the amount of matter in a body, also you could say the property of a body which represents the amount of resistance to being accelerated by an external force. This is a scalar quantity and usually represented in kilograms, Kg.

​5.__Weight__: this is the force on an object due to gravity. One way to define this is **W**=m**g**.

6. __Drag Force__: Forces that oppose the motion of a body through a fluid (gas or liquid). They are directed opposite to the velocity of the body and generally depend on the speed of that body. Higher speed equals higher drag force

7. __Normal Reaction Force__: If a body touches another body, there is a reaction force(R) between the two bodies. This force is perpendicular to the body exerting the force

8. Upthrust: An object placed in a fluid medium will experience upthrust. If the upthrust force on a body is equal to the weight, the body will float in the fluid [|Difference Between Buoyancy and Upthrust] from pediaa.com

2.3 Work, Energy and Power

Theories: Many phenomena can be fundamentally understood through application of the theory of conservation of energy. Over time, scientists have utilized this theory both to explain natural phenomena and, more importantly, to predict the outcome of previously unknown interactions. The concept of energy has evolved as a result of recognition of the relationship between mass and energy. (2.2)
 * // Nature of science: //**

• Kinetic energy • Gravitational potential energy • Elastic potential energy • Work done as energy transfer • Power as rate of energy transfer • Principle of conservation of energy • Efficiency
 * // Understandings: //**

• Discussing the conservation of total energy within energy transformations • Sketching and interpreting force–distance graphs • Determining work done including cases where a resistive force acts • Solving problems involving power • Quantitatively describing efficiency in energy transfers
 * // Applications and skills: //**

• ** Aim 6: ** experiments could include (but are not limited to): relationship of kinetic and gravitational potential energy for a falling mass; power and efficiency of mechanical objects; comparison of different situations involving elastic potential energy • ** Aim 8: ** by linking this sub-topic with topic 8, students should be aware of the importance of efficiency and its impact of conserving the fuel used for energy production
 * // Aims: //**

//** Data booklet reference: **//

Work = Force x Displacement x cosθ = <span style="color: #ff0000; font-family: &#39;Times New Roman&#39;; font-size: 16px;">Fscosθ || = = || Energy is ability to do work. Gravitational potential energy is that the possible energy an object has to transfer to kinetic energy due to being at a height above ground. GPE = mgh It is the result of its position in a gravitational field. Kinetic energy is the energy of motion.
 * Work is done when a force moves an object in the direction of the force. Work is a scalar quantity.
 * If the force and displacement are in the same direction, the formula simplifies to W = Fs because cos0 = 1
 * Work is a scalar quantity and is measured in Joules (J) or Newton metre (Nm) 1J = 1Nm ||
 * Work occurs when energy is transferred from one object to another.

KE = 1/2 (mv 2 ) Elastic potential energy is the possible energy stored in a compressed or stretched object (spring, elastic band etc). EPE = 1/2( kx 2 ) || Example question) A box with a mass of 20 kg is pushed 100 m up a frictionless incline that makes an angle of 40 degree with the horizontal. The box moves slowly at a constant speed. How much work did it take?

W=F x d W = (mg sinθ) d = (20kg x 9.81m/s 2 )(sin 40) (100m) = W= F x d = F x d cosθ = Δ E = Δ PE = mgΔh (Height = d sinθ) =

Power is the rate at which energy is transferred.

Power change in energy/time = work done/time = P = (ΔE/t) = W/t = The units for Power is Joules/second (Js-1) or Watts (W). Power is the rate of doing work. Unit is the watt

2.4 Moment and Impulse //** Nature of science: **// The concept of momentum and the principle of momentum conservation can be used to analyse and predict the outcome of a wide range of physical interactions, from macroscopic motion to microscopic collisions. (1.9)

//** Understandings: **// • Newton’s second law expressed in terms of rate of change of momentum • Impulse and force–time graphs • Conservation of linear momentum • Elastic collisions, inelastic collisions and explosions

//** Applications and skills: **// • Applying conservation of momentum in simple isolated systems including (but not limited to) collisions, explosions, or water jets • Using Newton’s second law quantitatively and qualitatively in cases where mass is not constant • Sketching and interpreting force–time graphs • Determining impulse in various contexts including (but not limited to) car safety and sports • Qualitatively and quantitatively comparing situations involving elastic collisions, inelastic collisions and explosions

//** International-mindedness: **// • Automobile passive safety standards have been adopted across the globe based on research conducted in many countries

//** Theory of knowledge: **// • Do conservation laws restrict or enable further development in physics?

//** Utilization: **// • Jet engines and rockets

//** Aims: **// • Aim 3: conservation laws in science disciplines have played a major role in outlining the limits within which scientific theories are developed • Aim 6: experiments could include (but are not limited to): analysis of collisions with respect to energy transfer; impulse investigations to determine velocity, force, time, or mass; determination of amount of transformed energy in inelastic collisions • Aim 7: technology has allowed for more accurate and precise measurements of force and momentum, including video analysis of real-life collisions and modelling/simulations of molecular collisions

//** Data booklet reference: **// Define linear momentum and impulse. <span style="background-color: #ffffff; font-family: Arial,Helvetica,sans-serif; font-size: 12px;">IMPULSE: The change in momentum. The effect of a force and the time the force is applied. A vector. Unit is Ns. <span style="background-color: #ffffff; font-family: Arial,Helvetica,sans-serif; font-size: 12px;">MOMENTUM: The quantity of motion of a moving body. The strength that an object has when it is moving. The property of tendency of a moving object to continue moving. <span style="background-color: #ffffff; font-family: Arial,Helvetica,sans-serif;">LINEAR MOMENTUM: the product of mass and velocity. It is a vector measured in kgms <span style="background-color: #ffffff; font-family: Arial,Helvetica,sans-serif; vertical-align: super;">-1

Impulse due to a time-varying force by interpreting a force–time graph.

<span style="background-color: #ffffff; font-family: &#39;Times CY&#39;;">LAW OF CONSERVATION OF LINEAR MOMENTUM: <span style="background-color: #ffffff; font-family: &#39;Times CY&#39;;">The momentum of an isolated system remains constant (ie when no external forces are acting). Or, in any isolated system, the change in momentum is zero. <span style="background-color: #ffffff; color: #1d1d1d; display: block; font-family: Georgia,"Times New Roman",Times,serif; font-size: 15px; text-align: justify;">[|Inelastic vs Elastic Collisions] An elastic collision is a collision where the colliding objects bounce back without undergoing any deformation or heat generation. An inelastic collision is a collision where the colliding objects are distorted and heat is generated. In an elastic collision, the momentum and total kinetic energy before and after the collision is the same. In other words, it can be said that the total kinetic energy and momentum are conserved during the elastic collision. So there is no wasting of energy in an elastic collision. An example of an elastic collision is the movement of the swinging balls.

In an inelastic collision, the energy changes into other energies such as sound energy or thermal energy. In an inelastic collision, the energy is not conserved. An example of an inelastic collision is an automobile collision. Read more from www.differencebetween.net

LINKS TO USEFUL DOCUMENTS:

[|IB Physics Topic 2 Energy and Momentum practice question.pdf] - markscheme for the above papers

[|Mechanics practice problem sets.pdf] [|Force and motion practice problems] [|Newton's laws of motion practice problems] from Eastern Illinois University [|Glenbrook 163 Forces questions] from mwit.co.th [|Forces exmaple questions] from www.physics247.com


 * [[image:Wet cloth in space.gif]] || media type="youtube" key="2PdiUoKa9Nw" width="560" height="315" ||
 * Wet cloth in space || [|The Cavendish Experiment]- Sixty Symbols <span class="view-count style-scope yt-view-count-renderer" style="color: var(--yt-metadata-color);"><span style="font-family: Roboto,Arial,sans-serif; font-size: 10px;">[|Sixty Symbols] Published on 6 Jul 2011 ||