OCR Physics P 4.4 Quiz

Alex is investigating the forces acting on a trolley to slow it down on different surfaces.

The figure shows his apparatus. Each time, he starts the trolley at the same marked point and measures how far it

goes along the test surface before it stops. The center of the trolley is marked with a dot. Here are measurements that Alex takes.

Mass of trolley = 0.80 kg

Height = 0.20 m

Assume gravitational field strength = 10 N/kg

Calculate the gravitational potential energy transferred when the trolley leaves the ramp.

Alex says that the kinetic energy of the trolley when it leaves the ramp is the same as the gravitational

potential energy transferred.

Which of the following statements must be true if Alex is to assume this? Select two answers.

• Air resistance is very small.

• Gravity acts downwards on the trolley.

• The ramp is very flat.

• The trolley is very light.

• There is not much friction acting on the trolley.

Alex repeats the experiment five times. He measures the distance the trolley travels along the test surface

each time. Calculate the mean distance the trolley traveled along the test surface.

George and Kate do an experiment with falling objects.

They use two balls of the same shape and size, but different masses.

They release the balls from the same height and find that they take the same time to drop to the floor.

Comment on their conclusions.

Use equations to justify your answer. [3 Marks]

Tamsin hits two balls with a bat.

The hard ball has a mass of 0.3 kg.

The soft ball has a mass of 0.2 kg.

Each ball gains the same momentum.

The hard ball will have the smaller velocity.

Explain why.

Tamsin hits two balls with a bat.

The hard ball has a mass of 0.3 kg.

The soft ball has a mass of 0.2 kg.

Each ball gains the same momentum.

TThe soft ball changes shape when hit so it is in contact with the bat for longer.

What effect will this have on the force acting on the soft ball?

Explain your answer. [2 Marks]

Tamsin hits two balls with a bat.

The hard ball has a mass of 0.3 kg.

The soft ball has a mass of 0.2 kg.

Each ball gains the same momentum.

The 0.3 kg hard ball hits a glass window with a speed of 4 m/s.

The glass will not break if the ball has a kinetic energy of less than 10 J.

Will the glass window break?

Use a calculation to help justify your answer. [3 Marks]

Tamsin hits two balls with a bat.

The hard ball has a mass of 0.3 kg.

The soft ball has a mass of 0.2 kg.

Each ball gains the same momentum.

The 0.2 kg soft ball hits the window at a speed of 6 m/s. It bounces back from the window at a speed of

4 m/s.

What is the change in momentum of the soft ball? [1 Mark]