1. Velocity and Acceleration Part 1
Exam Revision
Velocity and Acceleration Part 1

2. Of course, remember your equations
v = u + at
s = ut + (1/2)at2
s = vt – (1/2)at2
v2 = u2 + 2as
s = (u + v)t 2

3. Velocity
Remember that velocity and speed are different things. Speed gives you the magnitude while velocity is the magnitude and the direction.

4. Average velocity vs. average speed .
This matters when taking the average speed or velocity of an object.
Assume both these objects traveled from P to Q in 10 seconds. If the blue path is 25 meters long and the orange path is 20 meters long.
Avg. velocity(blue) = 2m/s
Avg. velocity(orange) = 2m/s
Avg. speed(orange) = 2m/s
Avg. speed(blue) = 2.5m/s

5. Average velocity vs. average speed .
Remember that total distance traveled and displacement are two different things, even though sometimes they have them same value.

6. Velocity-time graphs
Velocity-time graphs give us information about the velocity of an object, acceleration, displacement and distance traveled.
From 0 to 10 seconds the gradient of the line represents an acceleration of:
60m/s = 6m/s2
10s
What is the deceleration from 15 to 40 seconds?

7. Velocity-time graphs
Velocity-time graphs give us information about the velocity of an object, acceleration, displacement and distance traveled.
What is happening at the point when the line crosses the x-axis?
By the end of the graph where is the object?

8. Velocity-time graphs
Velocity-time graphs give us information about the velocity of an object, acceleration, displacement and distance traveled.
What is the average velocity of the object?
What is the distance traveled?
What is the average speed?

9. Velocity-time graphs
Velocity-time graphs give us information about the velocity of an object, acceleration, displacement and distance traveled.
What is the average velocity of the object?
What is the distance traveled?
What is the average speed?

10. Displacement Velocity Acceleration Displacement or position
Remember that in this
case we are talking about constant acceleration.
Velocity = ∆displacement
∆time
Acceleration = ∆velocity
Displacement
or position

11. Displacement Velocity Acceleration Remember that in this
cases we are talking about constant acceleration.
Velocity = ∆distance
∆time
Acceleration = ∆velocity

12. Practice problem #1.
The barrel of a shotgun is 0.9m long. The bullet comes out of the muzzle of the gun at a speed of 240m/s. What is the acceleration of the bullet in the barrel, and how long is the bullet in the barrel?

13. Practice problem #1.
The barrel of a shotgun is 0.9m long. The bullet comes out of the muzzle of the gun at a speed of 240m/s. What is the acceleration of the bullet in the barrel, and how long is the bullet in the barrel?
u = 0, v = 240, and s = 0.9
For acceleration use v2 = u2 + 2as
57600 = 1.8a
a = 32000m/s2
v = u + at
240 = * t
t = 32000/240 = s

14. Practice problem #2.
A 10m long truck is traveling at a constant speed of 96km/h. A driver of a 4m long car is following 35m behind and wants to pass. This car accelerates to 120km/h then immediately starts to decelerate all the way back to 96km/h. This takes 30 seconds and the car passes the truck. What is the new gap between the car and truck?

15. Practice problem #3.