logo   home

AQA GCSE

FORCES

(Speed, Acceleration, Forces, Weight, Graphs)

page 1

Choose the correct units for the following measurements :  
1. Mass
2. Weight
3. Velocity
4. Friction

The following questions are about a parachute jump.

 

A skydiver jumps out of a plane. Gravity pulls the person downwards. Air resistance pushes upwards. Later on they open the parachute.

They are shown here at the bottom of the jump.

 

Choose the sentences that best describe what happens:

  

5. Just after jumping out and before the parachute has been opened...

  • A). The air resistance decreases
  • B). The force of gravity increases as the person accelerates
  • C). The upward force increases
  • D). The 2 forces are always balanced

6. After a while the jumper reaches terminal velocity. This happens when

  • A). the air resistance and the force of gravity are balanced
  • B). the force of gravity increases more than the air resistance
  • C). air resistance is the largest force
  • D). the person is accelerating at a constant rate.

7. Which of these graphs shows the motion up to this point?

8. The person now opens his parachute. What happens now?

  • A). the air resistance and the force of gravity are balanced
  • B). the force of gravity decreases
  • C). the resultant force is now upwards
  • D). the person moves upwards as air resistance increases

9. A motor bike is travelling along a main road. If the forward force is 1kN and the backwards force bike is 500N , the resultant force on the bike is

  • A). 501N
  • B). 499N
  • C). 1500N
  • D). 500N

10. At one point in the journey, the bike is travelling at 20 m/s, the forward force is 500N and the backward force is 800N. The bike will now

  • A). accelerate
  • B). decelerate
  • C). stay at a constant speed
  • D). move backwards

11. Which of these is the correct formula for acceleration?

  • A). change in velocity x time taken
  • B). change in velocity / time taken
  • C). velocity x time taken
  • D). velocity / time taken

12. A train accelerates from 10 m/s to 50 m/s in 20 seconds. The acceleration is:

  • A). 2 m/s2
  • B). 2.5 m/s2
  • C). 800 m/s2
  • D). 1000 m/s2

These questions are about a lorry stopping when a dog jumps out into the road.

The table below shows the speed of the lorry at a time after the dog has jumped out.

Velocity (m/s)
time (s)
20
0
20
0.2
20
0.4
16
0.8
12
1.2
8
1.6
4
2.0
0
2.4

 

mad_dog

13. What was the driver's 'thinking' time?

14. What was the driver's braking time?
15. Calculate the lorry's deceleration in m/s2.

16. What 2 factors could have affected the driver's thinking time?

  • A). Poor brakes and tiredness
  • B). Alcohol and the weight of the lorry
  • C). Medical drugs and lack of sleep
  • D). The quality of the tires and the road conditions

17. If a car accelerates at - 3 m/s2, what does this mean?

  • A). It is moving backwards
  • B). It is slowing down
  • C). It is accelerating but 3 m/s2 less than before
  • D). It is accelerating, but the resultant force is backwards