Distance-time graphs

Two drivers race their cars in a straight line over a distance of 400 metres.

Figure 5 shows the cars.

Figure 6 shows a distance-time graph for one car in the race.

When was the car travelling at a constant speed?

Give a reason for your answer.

Tick () one box.

Between 2 seconds and 3 seconds

Between 3 seconds and 4 seconds

Between 4 seconds and 5 seconds

The two horizontal forces acting on the car were a driving force and air resistance.

How did the driving force compare with the air resistance when the car moved at a constant speed?

Give a reason for your answer.

Tick () one box.

The driving force was less than air resistance.

The driving force was the same size as air resistance.

The driving force was greater than air resistance.

At the end of the race, the driver applies the brakes and opens a parachute to decelerate the car.

Figure 7 shows one of the cars at the end of the race.

Why may it be dangerous for a car to have a very large deceleration?

Tick () one box.

The car engine may overheat.

The car will stop in a short distance.

The driver may lose control of the car.

Figure 17 shows a rugby player running with a rugby ball.

Use the Physics Equations Sheet to answer questions 08.1 and 08.2.

Which equation links distance (s), speed (v) and time (t)?

Tick () one box.

The rugby player travels a distance of 44 m in a time of 5.0 s.

Calculate the mean speed of the rugby player.

The rugby player collides with another player and stops.

Use the Physics Equations Sheet to answer questions 08.3 and 08.4.

Which equation links acceleration (a), change in velocity (Δv) and time (t)?

Tick () one box.

a = Δv × t

The velocity of the rugby player changes from 6.0 m/s to 0.0 m/s in a time of 400 ms.

Calculate the deceleration of the rugby player.

Figure 18 shows a rugby player wearing a ‘mouthguard’.

Mouthguards reduce the risk of injury when rugby players collide.

A mouthguard has been invented that transmits data about the deceleration of a rugby player’s head during a collision.

A deceleration of 540 m/s² or more automatically alerts the team doctor at the side of the rugby pitch.

Use the Physics Equations Sheet to answer questions 08.5 and 08.6.

Which equation links acceleration (a), mass (m) and resultant force (F)?

Tick () one box.

F = m × a

The mass of a rugby player’s head is 3500 g.

During a collision the rugby player’s head has a deceleration of 540 m/s².

Calculate the resultant force on the rugby player’s head.

Give one advantage of using the new mouthguard when playing rugby compared with a mouthguard that does not transmit data.

Figure 1 shows a rugby player running with a rugby ball.

Use the Physics Equations Sheet to answer questions 01.1 and 01.2.

Which equation links distance (s), speed (v) and time (t)?

Tick () one box.

The rugby player travels a distance of 44 m in a time of 5.0 s.

Calculate the mean speed of the rugby player.

The rugby player collides with another player and stops.

Use the Physics Equations Sheet to answer questions 01.3 and 01.4.

Which equation links acceleration (a), change in velocity (Δv) and time (t)?

Tick () one box.

a = Δv × t

The velocity of the rugby player changes from 6.0 m/s to 0.0 m/s in a time of 400 ms.

Calculate the deceleration of the rugby player.

Figure 2 shows a rugby player wearing a ‘mouthguard’.

Mouthguards reduce the risk of injury when rugby players collide.

A mouthguard has been invented that transmits data about the deceleration of a rugby player’s head during a collision.

A deceleration of 540 m/s² or more automatically alerts the team doctor at the side of the rugby pitch.

Use the Physics Equations Sheet to answer questions 01.5 and 01.6.

Which equation links acceleration (a), mass (m) and resultant force (F)?

Tick () one box.

F = m × a

The mass of a rugby player’s head is 3500 g.

During a collision the rugby player’s head has a deceleration of 540 m/s².

Calculate the resultant force on the rugby player’s head.

Give one advantage of using the new mouthguard when playing rugby compared with a mouthguard that does not transmit data.

A student investigated how the acceleration of a glider on an air-track varies with the mass of the glider.

Figure 14 shows the apparatus used.

The air blower allows the glider to move along the air-track with almost no friction.

The datalogger calculates the velocity of the glider as the glider passes through the light gate.

The resultant force acting on the glider was constant.

This is the method used.

1. Release the glider from rest at the end of the air-track.

2. Record the velocity of the glider from the datalogger.

3. Calculate the acceleration of the glider.

4. Repeat steps 1 to 3 two more times.

5. Repeat steps 1 to 4 using gliders of different mass.

Which two measurements does the datalogger need to determine the velocity of the glider?

Tick () two boxes.

Gravitational field strength

Length of card

Mass of glider

Temperature of surroundings

Time for card to pass light gate

Table 3 shows the results for a glider with a mass of 0.75 kg.

Determine the uncertainty in the recorded values of acceleration.

Uncertainty = ± ____________________ m/s²

Figure 15 shows the results.

The student concluded: ‘The acceleration of the glider was inversely proportional to the mass of the glider.’

Explain how the results in Figure 15 show that the student was correct.

A skydiver jumped out of a helicopter.

Figure 4 shows a distance–time graph for the first 12 seconds of the skydiver’s fall.

How does Figure 4 show that the speed of the skydiver increased between 1 second and 6 seconds?

Tick (✓) one box.

The gradient decreases

The gradient stays the same

The gradient increases

What happened to the speed of the skydiver between 8 seconds and 12 seconds?

Use Figure 4.

Tick (✓) one box.

The speed decreased

The speed stayed the same

The speed increased

Determine the mean speed of the skydiver between 0 seconds and 12 seconds.

Use Figure 4 and the equation:

The forces acting on the skydiver during the fall were weight and air resistance.

What happened to the weight of the skydiver during the fall?

Tick (✓) one box.

Weight decreased

Weight stayed the same

Weight increased

What happened to the air resistance acting on the skydiver as the speed of the skydiver increased?

Tick (✓) one box.

Air resistance decreased

Air resistance stayed the same

Air resistance increased

The skydiver reached terminal velocity.

How did the forces acting on the skydiver compare at terminal velocity?

Tick (✓) one box.

Which of the following shows the velocity–time graph for the skydiver falling at terminal velocity?

Tick (✓) one box.

The skydiver decelerated when the parachute opened.

The initial resultant force on the skydiver was 960 N.

The mass of the skydiver was 64 kg.

Calculate the initial deceleration of the skydiver.

Use the equation:

Choose the unit from the box.

A skydiver jumped out of a helicopter.

Figure 8 shows a distance-time graph for the first 12 seconds after the skydiver jumped out of the helicopter.

Determine the speed of the skydiver between 8 and 12 seconds.

Use the Physics Equations Sheet.

Describe how the motion of the skydiver changed between 0 and 12 seconds.

Explain why the resultant force on the skydiver changed as the skydiver fell.

Which of the velocity–time graphs shows how the velocity of the skydiver changed after the parachute was opened?

Tick (✓) one box.

Figure 10 shows a boat on the sea.

The boat is travelling at a constant speed.

Draw an arrow on Figure 10 to show the size and direction of the force of the water on the propeller.

A quantity can be a scalar quantity or a vector quantity.

Identify which quantities are scalar quantities and which quantities are vector quantities.

Tick (✓) one box in each row.

Which equation links distance (s), speed (v) and time (t)?

Tick (✓) one box.

The speed of the boat is 12 m/s.

Calculate the time taken to travel 6000 m.

Use the Physics Equations Sheet.

Figure 11 shows the forces acting on the boat when it is moving at a constant speed.

The engine of the boat is turned off. The boat slows down and stops.

Explain what happens to the forces acting on the boat.

Figure 2 shows a boat on the sea.

The boat is travelling at a constant speed.

Draw an arrow on Figure 2 to show the size and direction of the force of the water on the propeller.

A quantity can be a scalar quantity or a vector quantity.

Identify which quantities are scalar quantities and which quantities are vector quantities.

Tick (✓) one box in each row.

Which equation links distance (s), speed (v) and time (t)?

Tick (✓) one box.

The speed of the boat is 12 m/s.

Calculate the time taken to travel 6000 m.

Use the Physics Equations Sheet.

Figure 3 shows the forces acting on the boat when it is moving at a constant speed.

The engine of the boat is turned off. The boat slows down and stops.

Explain what happens to the forces acting on the boat.

A scalar quantity has size, but no direction.

Distance is a scalar quantity.

Which of the following is a scalar quantity?

Tick (✓) one box.

Acceleration

Speed

Velocity

Weight

Figure 6 shows the route a car travelled from town P to town Q.

The displacement of the car is the straight-line distance from town P to town Q.

Determine the displacement of the car when the car has travelled from town P to town Q.

Include the direction from north.

At one point in the journey the car had an acceleration of 0.12 m/s².

The car has a mass of 800 kg.

Calculate the resultant force on the car.

Use the equation:

resultant force = mass × acceleration

Figure 7 shows a distance-time graph for a different part of the car’s journey.

Determine the speed of the car.

Figure 10 shows a cyclist on a straight, level road.

At one point in the journey the cyclist’s velocity changed from 5.0 m/s to 9.0 m/s in a time of 2.5 s.

Calculate the acceleration of the cyclist.

Use the equation:

Choose the unit from the box.

The maximum speed of the cyclist was 15 m/s.

The cyclist travelled at this speed for 60 s.

Calculate the distance travelled by the cyclist during this time.

Use the equation:

distance travelled = speed × time

The maximum speed of this cyclist is much higher than the typical mean speed of a cyclist.

What is the typical mean speed of a cyclist?

Tick (✓) one box.

1.5 m/s
3.0 m/s
6.0 m/s

Give two factors that would decrease the maximum speed of a cyclist on a journey.

At the end of the journey the cyclist decelerates from a speed of 15 m/s and stops.

The deceleration of the cyclist is 5 m/s².

Calculate the distance travelled while decelerating.

Use the Physics Equations Sheet.

Figure 10 shows a girl inside a train which is moving to the left at a speed of 20 m/s

The girl is wearing inline skates.

The train is moving at a constant speed of 20 m/s

The train suddenly decelerates.

The girl continues to move with a speed of 20 m/s

Which of Newton’s laws is a correct explanation of this situation?

Tick (✓) one box.

Figure 11 shows a velocity-time graph for the train as it arrives at a station and stops.

Between which two times on Figure 11 is the train stationary?

Tick (✓) one box.

The train travels at a constant speed between 0 seconds and 5 seconds.

Determine the distance the train travels between 0 seconds and 5 seconds.

Use the equation:

distance travelled = speed × time

Between which two times on Figure 11 is the deceleration of the train the greatest?

Write down the equation which links acceleration (a), change in velocity (Δ v) and time taken (t).

Determine the acceleration of the train between 15 seconds and 20 seconds.

Write down the equation which links kinetic energy (E_k), mass (m) and speed (v).

At one point in the train’s journey the train’s speed was 6.0 m/s

At this point the kinetic energy of the train was 1 080 000 J

Calculate the mass of the train.

A student investigated how the acceleration of a trolley varied with the resultant force on the trolley.

The force on the trolley was provided by the masses on the string.

Figure 16 shows how the student set up the equipment.

This is the method used.

1. Release the trolley from the top of the runway.

2. As the card passes each light gate a timer turns on and off.

3. The datalogger calculates the velocity of the trolley at light gate A and at light gate B.

4. The datalogger calculates the acceleration using the two velocities.

5. Repeat steps 1 to 4 using different masses.

Which two measurements are needed to determine the velocity of the trolley at each light gate?

Tick (✓) two boxes.

Why was a sloping runway used instead of a flat runway?

Tick (✓) one box.

What are two advantages of using a datalogger and light gates instead of a stopclock in this investigation?

Tick (✓) two boxes.

Write down the equation which links acceleration (a), mass (m) and resultant force (F).

The acceleration of the trolley was 2.4 m/s²

The resultant force on the trolley was 1.2 N

Calculate the mass of the trolley.

A student investigated how the acceleration of a trolley varied with the resultant force on the trolley.

The force on the trolley was provided by the masses on the string.

Figure 5 shows how the student set up the equipment.

This is the method used.

1. Release the trolley from the top of the runway.

2. As the card passes each light gate a timer turns on and off.

3. The datalogger calculates the velocity of the trolley at light gate A and at light gate B.

4. The datalogger calculates the acceleration using the two velocities.

5. Repeat steps 1 to 4 using different masses.

Which two measurements are needed to determine the velocity of the trolley at each light gate?

Tick (✓) two boxes.

Why was a sloping runway used instead of a flat runway?

Tick (✓) one box.

What are two advantages of using a datalogger and light gates instead of a stopclock in this investigation?

Tick (✓) two boxes.

Write down the equation which links acceleration (a), mass (m) and resultant force (F).

The acceleration of the trolley was 2.4 m/s²

The resultant force on the trolley was 1.2 N

Calculate the mass of the trolley.