Unit+1+General+Physics

// ** 1.2 Motion (Speed, velocity and acceleration) ** //
LOs: 1. Define speed and calculate average speed from total distance /total time 2. Plot and interpret a speed-time graph or a distance-time graph 3. Recognise from the shape of a speed-time graph when a body is – at rest – moving with constant speed – moving with changing speed

* What is the definition of speed? * What is the formula for average speed? * How can we know the instantaneous speed of an object? If we consider a body that is initially pushed and gradually stops after a time, then the **average velocity** can be found:
 * __Average Velocity__**


 * ==V av === || ====**__Total distance travelled__**====

**Total time taken**
|| e.g. Total distance was 1m Total time was 2s V av = 1m /2s = 0.5m/s Even though it is slowing down (decelerating), it still has an average velocity.

**__Instantaneous Velocity__** This is the velocity of a body at an instant in time. ie) a very small distance and a very small time.


 * ==v === || ====**__Δ d__**====

**Δ t**
|| Δ is small change d is displacement t is time ||

__Words and the concepts__ from physicsclassroom.com
=** 1.5.5 Scalars and vectors **= • Understand that vectors have a magnitude and direction • Demonstrate an understanding of the difference between scalars and vectors and give common examples • Determine graphically the resultant of two vectors = Scalars and Vectors = **Scalar:** A quantity, such as mass, length, or speed, that is completely specified by its magnitude and has no direction.(ex: speed, time, temperature, distance) **Vector:** A quantity, such as force, completely specified by a magnitude and a direction.(ex: velocity, displacement)
 * 1) [|Scalars and Vectors]
 * 2) [|Distance and Displacement]
 * 3) [|Speed and Velocity]
 * 4) [|Acceleration]
 * 5) Average vs Instantaneous Speed
 * Supplement**
 * Distance || How much path is covered by an object, regardless of its starting or ending position. ||
 * Displacement || An object's change in position with the relation to its starting position and final position. Change in spatial location. ||

//__ Steps to solving component problems __// 1. Draw vector diagram 2. Pick two perpendicular directions to resolve your components into. 3. Resolve each vector into its components where necessary. 4. Add up all the components in each direction. 5. Make a new right triangle using the component sums. 6. Find the resultant magnitude and direction of the triangle.  Some worksheets from [|Mr. D Physics Weebly page] [|Vector addition practice questions] from physics.info
 * [[image:http://www.weebly.com/weebly/images/file_icons/pdf.png width="36" height="36" link="http://mrdphysics.weebly.com/uploads/1/1/7/9/11797812/vectors_lecture.pdf"]] [|Vectors notes] || [[image:http://www.weebly.com/weebly/images/file_icons/pdf.png width="36" height="36" link="http://mrdphysics.weebly.com/uploads/1/1/7/9/11797812/vector_basics_wkst.pdf"]] [|Vector basic workshee] || [[image:http://education.weebly.com/weebly/images/file_icons/pdf.png width="36" height="36" link="http://mrdphysics.weebly.com/uploads/1/1/7/9/11797812/chapter_3.pdf"]] [|More worksheet] ||

[|Vectors rule Garibaldi Secondary School Physics] //__Keywords:__// Magnitude: greatness of size or amount. The amount without direction. The numerical amount of the quantity. Direction: The course or line along which a person or thing moves, points, or lies. Distance: The length or numerical value of a straight line or curve. Displacement: Straight line distance between initial and final points.

Vector simulation from Phet media type="custom" key="23718398" [|Resultant vectors] from Physicsclassroom.com

Displacement vs Time graph from www.absorblearning.com
media type="youtube" key="9LQdLDDEJ1g" width="560" height="315" [|Distance vs Time graphs & speed] GCSE Science Shorts Sketch from youtube.com
 * [[image:Displacement Time.gif width="277" height="190"]] || Between

OA; A body moves with uniform displacement (Constant velocity)

AB; NO movement (0m/s)

BC; Slower constant velocity

The steeper the gradientt the larger the velocity. || Describing Motion with Position vs. Time Graphs from physicsclassroom.com Graphing speeds Interpretation || Example 2 Interpretation || Example 3 Interpretation || AVERAGE SPEED, INSTANTANEOUS SPEED, SI UNIT, How does the D-T graph look like when speed increases/decreases?
 * 1) [|The Meaning of Shape for a p-t Graph]
 * 2) [|The Meaning of Slope for a p-t Graph]
 * 3) [|Determining the Slope on a p-t Graph]
 * [[image:Distance Time Graph Fig1.jpg width="338" height="189"]] || [[image:Displacement Time Graph Fig2.jpg width="244" height="195"]] || [[image:Displacement Time Graph Fig3.jpg]] ||
 * Example 1

LOs: 1. Calculate the area under a speed-time graph to work out the distance travelled for motion with constant acceleration 2. Demonstrate some understanding that acceleration and deceleration are related to changing speed including qualitative analysis of the gradient of a speed-time graph 3. State that the acceleration of free fall for a body near to the Earth is constant Distinguish between speed and velocity Define and calculate acceleration using change of velocity/time taken Calculate speed from the gradident of a distance-time graph Calculate acceleration from the gradient of a speed-time graph Recognise linear motion for which the acceleration is constant • Recognise motion for which the acceleration is not constant • Understand deceleration as a negative acceleration
 * Supplement**

Speed vs Time graph

 * [[image:Velocity Time.gif width="277" height="209"]] || Between

AB; A body moves with a constant velocity

BC; The body is accelerating uniformly

CD; The body is decelerating uniformly ||

Velocity vs Time graph from physicsclassroom.com
Describing Motion with Velocity vs. Time Graphs from physicsclassroom.com media type="youtube" key="4iI7f4xw0Bk" width="560" height="315" [|Determining the meaning of slope in Distance Time vs Velocity Time graphs] from youtube.com media type="youtube" key="3x22CpSB7zM" width="560" height="315" [|Speed vs Time graphs and acceleration] GCSE Science Shorts Sketch from youtube.com Example)
 * 1) [|The Meaning of Shape for a v-t Graph]
 * 2) [|The Meaning of Slope for a v-t Graph]
 * 3) [|Relating the Shape to the Motion]
 * 4) [|Determining the Slope on a v-t Graph]
 * 5) [|Determining the Area on a v-t Graph]
 * = Displacement vs Time ||= Velocity vs Time ||
 * [[image:D-T.gif width="272" height="194"]] || [[image:V-T.gif width="267" height="194"]] ||

Acceleration from physicsclassroom.com
Acceleration is the rate of change of __ velocity __ It can be found by finding out its initial velocity.(starting velocity) and its final velocity, and the time it took to change. time taken to change velocities || v is finial velocity, u is initial velocity, t is time || Example 1). A car starts from rest and accelerates uniformly to a velocity of 40m/s in 20s. Find its acceleration. SOLUTION: a = ( v - u ) / t  a = (40 -0) / 20 = 2  a = 2 m/s 2
 * **Acceleration** = || __(Final velocity - initial velocity)__
 * a = (v - u ) / t || a is acceleration,

//**Let's practise some questions before we move on to the uniform acceleration.**// 1.The brown bear, starting from rest, can run 18 m/s (approximately 40mph) in 10 seconds. What is the acceleration of the bear?

2. How far will the bear run in these 10 seconds?

3. If you run 5.4m/s how far will you run in 10 seconds ?

4. How much of a head start will you need if your cabin is 100m away?

5. Falling objects drop with an average acceleration of 9.8 m/sec/sec/ or 9.8 m/sec to second. If an object falls from a tall building, how long will it take before it reaches a speed of 49 m/sec?

6. After this time, how far has it fallen

7. A driver starts his parked car and within 5 sec reaches a velocity of 54 km/hr as he travels east. What is his acceleration?

8. What is his final displacement from his starting position?

9. The acceleration of a top thrill dragster is 60mi/hr per second. How fast will this vehicle be traveling in 5 seconds?

10. How far will it have traveled in 5 seconds.

11. In the first 5 seconds of its path, a cheetah travels 20m. In the second 5 seconds of its path, it travels 100m. What was the cheetah’s initial and final speed?

12. What was the cheetah’s acceleration?

13. In order to save Mary-Jane from dying, Spiderman needs to jump from one building on to another but wants the jump to last only 3 seconds. He is jumping straight down from a building 300m tall. How tall does this second building have to be for Spiderman to be able to save her life?

14. How fast would Spiderman be falling right before he landed on this building?

15. You want to drop an egg on Mr. Peers’s head but need it to be traveling at least 90 m/s. How long will the egg have to be falling in order for you to complete your goal?

16. How tall of a building do you need to be on in order to ensure the egg is in the air this long?

Motion with Constant Acceleration from www.walter-fendt.de Constant acceleration motion graphs from hyperphysics.edu Free Fall and the Acceleration of Gravity from physicsclassroom.com
 * 1) [|Introduction to Free Fall]
 * 2) [|The Acceleration of Gravity]
 * 3) [|Representing Free Fall by Graphs]
 * 4) [|How Fast? and How Far?]

Motion revision graphs from TES Additional Science: Motion Test from TES Markscheme for your revision paper

Acceleration 1 from Eureka episodes media type="file" key="Acceleration1.flv" width="324" height="243" Acceleration 2 from Eureka episodes media type="file" key="Acceleration Part II.flv" width="324" height="243" __ Equations of motion __ from schoolphysics.co.uk  Various motion graphs from physics20project.weebly.com Practice questions (Be sure to show your work!) 1. A train is traveling at the speed of 10m/s at the top of a hill. Five seconds later it reaches the bottom of the hill and is moving at 30m/s. What is the rate of acceleration of the train? 2. Pete, the Penguin loves to sled down his favorite hill. If he hits a speed of 50m/s after 5 seconds, what is his rate of acceleration? 3. A truck decelerates from 72m/s to 0m/s in 6 seconds. What is his rate of deceleration?

Homework due by 7th Sep. 2016
Do questions on your text • Distinguish between speed and velocity: Click the link and solve the quizz on accleration, speed and velocity
 * Supplement**

LOs • Recognise linear motion for which the acceleration is constant and calculate the acceleration • Recognise motion for which the acceleration is not constant • Understand deceleration as a negative acceleration • Describe qualitatively the motion of bodies falling in a uniform gravitational field with and without air resistance (including reference to terminal velocity)

[|Conceptual Motion Problems and Solution] from physicscatalyst.com [|Speed revision from the Hypertextbook] //**Conceptual 2)**// EXPLORATION QUESTION 1:  media type="youtube" key="EabUUrZFnFE" width="560" height="315" [|Terminal velocity on a skydiver] [|Mr Riddz Science] Published on 18 Jun 2014 For your notes; <span style="background-color: #ffffff; color: #58646d; font-family: "Helvetica Neue","Lucida Grande","Segoe UI","Trebuchet MS",Verdana,Arial,Helvetica,sans-serif; font-size: 14px;">1. Write the definition of Terminal velocity. ( Steady velocity in a falling object when the resultant force acting on them is zero. )
 * //Conceptual question1)//**
 * =**//Can the velocity of an object reverse direction when its acceleration is constant? If so, give an example; if not, explain why?//**=
 * //**A person standing on the edge of a cliff at some height above the ground throws one ball straight up with initial speed, V𝑖 and then throws another ball straight down with the same initial speed. Which ball, if either, has the larger speed when it hits the ground? Neglect air resistance.**//

<span style="background-color: #ffffff; color: #58646d; font-family: "Helvetica Neue","Lucida Grande","Segoe UI","Trebuchet MS",Verdana,Arial,Helvetica,sans-serif; font-size: 14px;">2. Plot a graph of "Velocity vs Time" using the video clip.

<span style="background-color: #ffffff; color: #58646d; font-family: &#39;Helvetica Neue&#39;,&#39;Lucida Grande&#39;,&#39;Segoe UI&#39;,&#39;Trebuchet MS&#39;,Verdana,Arial,Helvetica,sans-serif; font-size: 14px;">3. Indicate the sections of terminal velocity and when the parachute opened.

<span style="background-color: #ffffff; color: #58646d; font-family: &#39;Helvetica Neue&#39;,&#39;Lucida Grande&#39;,&#39;Segoe UI&#39;,&#39;Trebuchet MS&#39;,Verdana,Arial,Helvetica,sans-serif; font-size: 14px;">4. Describe the change of the motion of a parachutist along with forces acting on the parachutist.

<span style="background-color: #ffffff; color: #58646d; font-family: &#39;Helvetica Neue&#39;,&#39;Lucida Grande&#39;,&#39;Segoe UI&#39;,&#39;Trebuchet MS&#39;,Verdana,Arial,Helvetica,sans-serif; font-size: 14px;">5. Show your notes to Ms. Lee.

<span style="background-color: #ffffff; color: #58646d; font-family: &#39;Helvetica Neue&#39;,&#39;Lucida Grande&#39;,&#39;Segoe UI&#39;,&#39;Trebuchet MS&#39;,Verdana,Arial,Helvetica,sans-serif; font-size: 14px;">6. Click the link Skydiving <span style="background-color: #ffffff; color: #58646d; font-family: "Helvetica Neue","Lucida Grande","Segoe UI","Trebuchet MS",Verdana,Arial,Helvetica,sans-serif; font-size: 14px;"> to check your forces diagrams. [|Velocity Time graph of skydiving] from www.tes.com

Describe the motion of a falling object without air resistance media type="youtube" key="E43-CfukEgs" width="560" height="315" BBC TWO [|Brian cox visits the world largest vacuum chamber]from youtube.com

<span style="font-family: "Calibri Light",sans-serif;">Challenge QUESTION 1: Does the total weight decrease, if weight drops in a closed container? <span style="font-family: "Calibri Light",sans-serif;">media type="youtube" key="MEXKwK6NGSM" width="560" height="315" [|If a Weight Drops In a Closed Container Does the Total Weight Decrease?] <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: var(--yt-formatted-string-endpoint_-_font-size);">[|The Action Lab] Published on 14 Dec 2017

** Practical assignment; Investigating acceleration **
Report should be done in below format 1) Microsoft Word 2003 2) Double line spacing 3) Font size 12 Times New Roman 4) Due date: 8th September 2016 Date of this document: 25th August 2016

Practical Write Up

Guidelines for plotting graph: [|Graph Guidelines.ppt]

[|How big is the space] from BBC

Thanks SH for 'Acceleration due to gravitational force on Earth' Investigation Report