Stopping distances, Circular Motion, Momentum, Free Body Diagrams

Topics 2 and 9 (paper 1 and 2)

1-6: These questions are about a lorry stopping when a dog jumps out into the road.

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

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

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

2. How far did the lorry travel in this time?

3. What was the driver's braking time?

4. Calculate the lorry's deceleration in m/s2.

5. 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

6. What 2 factors could affect the driver's braking 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

7. What is the name of the force that causes circular motion, and in which direction does it act?

• A). Centripetal force, acting forwards.
• B). Centripetal force, acting towards the centre of the circle.
• C). Centrifugal force, acting forwards.
• D). Centrifugal force, acting towards the centre of the circle.

8. As the Earth orbits the Sun, which measurement is constantly changing?

• A). The size of the force causing circular motion
• B). The velocity of the Earth
• C). The speed of the Earth
• D). The distance between the Earth and the Sun

9+10. A remote controlled car is switched on and accelerates from rest.

9.Which of these 4 free body diagrams correctly shows the relative sizes of the forces acting on the car?

10. The car is hard to accelerate if the mass is larger. This is called the car's ...

• A). inertial mass
• B). gravitational mass
• C). atomic mass
• D). molar mass