1. General physics

1.1 Length and time
LOs:
• Use and describe the use of rules and measuring cylinders to find a length or a volume
• Use and describe the use of clocks and devices, both analogue and digital, for measuring an interval of time
Supplement
• Understand that a micrometer screw gauge is used to measure very small distances

Activity
Measure at least 5 lab equipment without using any measuring device such as a ruler, measuring cylinder.
1. What are the lab equipment that you have chosen to measure?
2. What sort of things have you used to measure the lab equipment?
3. Do you know what is the most distance galaxy ever measured? Can you measure the distance using a regular ruler? What measurement do you use? What is the unit of it?
4. Do you think they are reliable for accurate or precise measurement?
5. What can you think of to prevent any ‍‍‍‍mistakes/errors‍‍‍‍ to measure a material?

Task
Find the thickness of your notebook paper and the size of a head of iron nail.

Caliper: an instrument for measuring the distance between two point

Video clip: Metric and standard measurement from Youtube.com
1. Make a list of the SI Units.
2. Learn how to use a vernier caliper and micrometer.
How to use a vernier caliper?


Classwork ( 12th Aug. 2016) ;
1. Make a list of the SI Units.
2. Learn how to use a vernier caliper and micrometer.
3. Describe the 2 uses of a mechanical method for the measurement of a small distance.
4. Measure and describe how to measure a short interval of time such as the period of a pendulum.
How to use a micrometer? from Youtube.com


Homework by Wednesday ( Due G1:Monday 15 Aug. G2:Tuesday16 Aug)

1. Read text p14, 15 and take notes
2. Do questions 1, 2 and 3 (p15)
Significant figures from GCSE Bitesize

LO: Obtain an average value for a small distance and for a short interval of time by measuring multiples (including the period of a pendulum)
Pendulum Experiment
Length
Time for 20 oscillations
Period
T2
l/m
t/second
T/s
T2/s2
0.600



0.700



0.800



0.900



1.000




Length
Time for 20 oscillations
Period
T2
l/m
t/second
T/s
T2/s2
0.600



0.700



0.800



0.900



1.000




Q1. Describe how you would find the thickness of a sheet of paper by using a micrometer.
Check zero point.
Close micrometer onto paper. Lock the micrometer.
Take the reading of both scales of barrel and thimble.

Q2. Describe how you can make the above experiment a fair test.
Try the above procedure several times.
Measure the thickness of paper using several sheets of paper then divided it by the number of piece of paper.

Q3. Describe and explain why how you would determine the period as accurately as possible.
Measure the time for 20 complete oscillations, divide the measured time by 20. The reason why we measure the time for 20 swings then divides it by 20 is to make the measurement more accurate.


1.4 Density

LO:
Recall and use the equation ρ =m/V
• Describe an experiment to determine the density of a liquid and of a regularly shaped solid and make the necessary calculation
• Describe the determination of the density of an irregularly shaped solid by the method of displacement
• Predict whether an object will float based on density data



The density of an object is relative to two things;
  • MASS
  • VOLUME
It can be calculated like this;
Density equation.jpg
Image from http://erinschumacher.com

ρ = m/V

where ρ (rho) is density,
m is mass,
V is volume

units of density are kg/m3 , kgm-3 or g/cm3

Example)
2000 kg of water occupies 2m3 of volume
Its density is
ρ = 2000/2 = 1000kg/m3

Activity
Measure the density of different materials such as a rock, milk, an apple and a piece of toast bread.

Task
Design a practical write up to investigate the density of different 3 materials including a solid, a solid in irregular shape and liquid material).

Extension:
Describe the determination of the density of an irregularly shaped solid by the method of displacement, and make the necessary calculation


Density from Eureka episode

Homework by
1. Do questions on the text
2. Complete the practical write up on density investigation that you designed during the class.

Homework by Monday
1. Make a summary after reading the text
2. Complete the end of chapter questions of unit 1.
3. Submit your practical write up on density investigation.

Q1. What precaution should be taken when using a measuring cylinder?
Make sure that the measuring cylinder is vertical.
Make sure that the eye is levelled with the liquid surface(meniscus), avoiding parallax error.

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?

Average Velocity
If we consider a body that is initially pushed and gradually stops after a time, then the average velocity can be found:

Vav =

Total distance travelled

Total time taken

e.g.
Total distance was 1m
Total time was 2s
Vav = 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

  1. Scalars and Vectors
  2. Distance and Displacement
  3. Speed and Velocity
  4. Acceleration
  5. Average vs Instantaneous Speed
from physicsclassroom.com

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)
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

external image pdf.pngVectors notes
external image pdf.pngVector basic workshee
external image pdf.pngMore worksheet

Vector addition practice questions from physics.info


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

Resultant vectors from Physicsclassroom.com

Displacement vs Time graph

from www.absorblearning.com

Distance vs Time graphs & speed GCSE Science Shorts Sketch from youtube.com
Displacement Time.gif
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.
  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
Describing Motion with Position vs. Time Graphs from physicsclassroom.com
Graphing speeds
Distance Time Graph Fig1.jpg
Displacement Time Graph Fig2.jpg
Displacement Time Graph Fig3.jpg
Example 1
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?

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
Supplement
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

Speed vs Time graph

from physicsclassroom.com
Velocity Time.gif
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

  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
Describing Motion with Velocity vs. Time Graphs from physicsclassroom.com
Determining the meaning of slope in Distance Time vs Velocity Time graphs from youtube.com
Speed vs Time graphs and acceleration GCSE Science Shorts Sketch from youtube.com
Example)
Displacement vs Time
Velocity vs Time
D-T.gif
V-T.gif

Acceleration

from physicsclassroom.com

This is the rate of change of speed/velocity
Acceleration can be found by finding out its initial velocity.(starting speed) and its final velocity, and the time it took to change.

Acceleration =
(Final velocity - initial velocity)
time taken to change velocities
a = (v - u ) / t
a is acceleration,
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.

a = ( v - u ) / t
a = (40 -0) / 20 = 2
a = 2 m/s2

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
  1. Introduction to Free Fall
  2. The Acceleration of Gravity
  3. Representing Free Fall by Graphs
  4. How Fast? and How Far?
Free Fall and the Acceleration of Gravity from physicsclassroom.com

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


Acceleration 1 from Eureka episodes


Acceleration 2 from Eureka episodes


Equations of motion from schoolphysics.co.uk
Various motion graphs from physics20project.weebly.com
external image file.cfm?9F12D872036DA85B


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

Supplement
• Distinguish between speed and velocity: Click the link and solve the quizz on accleration, speed and velocity

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)

Speed revision from the Hypertextbook

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 your 'Acceleration due to gravitational force on Earth' Investigation Report