Contact and non-contact forces

Ice hockey is a team sport played on ice. Players try to hit a disc called a puck into the other team’s goal.

(Source: © Alexandr Grant / Shutterstock)

Diagram 1 shows a puck travelling across some smooth ice.

State the formula linking average speed, distance moved and time taken.

The puck travels at a constant speed of 2.8 m/s.

Calculate the distance moved by the puck in a time of 3.5 s.

Diagram 2 shows a puck travelling across some rough ice.

The rough ice exerts a frictional force on the puck.

Draw a labelled arrow on diagram 2 to show the force of friction acting on the puck.

Explain how the force of friction changes the velocity of the puck.

Diagram 1 shows a planet orbiting a star, and a moon orbiting a planet.

On Diagram 1, draw the orbit of a comet around the star.

On Diagram 1, draw an arrow to show the force the planet exerts on the moon.

What type of force does the planet exert on the moon?

The planet completes one orbit of the star in a time of 2.510⁸s.

The radius of the planet’s orbit is 8.710¹⁰m.

Calculate the orbital speed of the planet.

Give your answer to two significant figures.

Diagram 2 shows the region around the Sun, a yellow star, where liquid water can exist on the surface of planets. This is because the surface temperature of the planet is between 0C and 100C.

Explain what would happen to the position of the liquid water region if the Sun was replaced with a blue star of the same size.

In 1947, the Railton Mobil Special was the first ground vehicle to achieve a speed of more than 400 miles per hour.

During a test, the vehicle travelled at a speed of 403 miles per hour.

Calculate a speed of 403 miles per hour in metres per second (m / s). [1 mile = 1600 m]

During the test, the vehicle travelled past two markers. The markers were placed a known distance apart.

Describe how these markers could be used to determine the speed of the vehicle.

The diagram shows the vehicle travelling at a constant speed.

One of the horizontal forces acting on the vehicle has been drawn.

Complete the diagram by drawing a labelled arrow for the other horizontal force acting on the vehicle.

A student stretches a rubber band.

The photographs show a rubber band before and after it has been stretched.

State which energy store increases in the rubber band after it has been stretched.

State the main method of energy transfer when the rubber band is stretched.

State the source of the energy transferred to the rubber band.

The diagram shows a force-extension graph for a rubber band.

State how the graph shows that the rubber band does not obey Hooke’s law.

Explain how the graph shows that the rubber band is elastic.

The student stretches the rubber band and then releases it. The band moves vertically upwards.

The band travels with an initial speed of 13 m / s.

When the band reaches its maximum height above the student’s hand, the band has a speed of 0 m / s.

Calculate the maximum height that the band reaches.

Give your answer to 2 significant figures.

[acceleration due to gravity = −10 m / s²]

The band reaches its maximum height.

Explain the motion of the band as it falls from its maximum height to the ground.

Refer to forces in your answer.

You may assume

• the band does not rotate

• the band does not reach terminal velocity

A car accelerates with a constant driving force along a horizontal road and reaches its maximum speed.

This is the velocity-time graph for the car’s journey.

By drawing a tangent to the curve, determine the acceleration of the car at a time of 20 s.

acceleration =_........ ²

Determine the distance travelled by the car during the first 80 s of its journey.

Explain the motion of the car after 80 s.

The photograph shows the International Space Station (ISS) in orbit around the Earth.

The ISS orbits the Earth in a circular orbit.

Which of these also orbits the Earth?

Which of these forces causes the ISS to orbit the Earth?

The ISS completes one orbit of the Earth in a time period of 93 minutes.

The orbital radius of the ISS is 6.810³km.

Calculate the orbital speed of the ISS in km / s.

orbital speed =_........ km / s

Show that the ISS completes approximately 15 orbits of the Earth each day.

The diagram shows a balloon with a mass attached held at rest just below the surface of a deep pool of water.

The balloon and mass are released.

The graph shows the velocity-time graph for the balloon and mass as they fall through the water.

Use information from the graph to determine the terminal velocity of the balloon and mass.

Explain how the balloon reaches terminal velocity.

You should use ideas about forces acting on the balloon in your answer.

State the formula linking pressure difference, height, density and gravitational field strength.

Calculate the increase in pressure on the balloon when it has reached a depth of 25 m in the water.

[for water, density = 1000 kg/m³]

At the surface, the atmospheric pressure on the balloon is 1.010⁵Pa.

Show that the total pressure on the balloon at a depth of 25 m is 3.510⁵Pa.

At the surface, where the pressure is 1.010⁵Pa, the balloon has a volume of 0.46 m³.

Calculate the volume of the balloon at a depth of 25 m.

The diagram shows a child on a zip-line ride.

During the ride the child slides along a metal wire with the velocity in the direction shown in the diagram.

The diagram also shows the tension force acting on the safety harness the child is wearing.

Force and velocity are examples of vector quantities.

State what is meant by the term vector quantity.

Draw labelled arrows on the diagram to show two other forces that act on the child.

This question is about a parachutist.

A parachutist leaves a helicopter that is hovering above the ground.

The parachutist is initially at rest and falls vertically downwards.

Calculate the speed of the parachutist after they have fallen through a distance of 1300 m.

Ignore the effect of air resistance.

When the parachutist is much nearer to the ground, they open their parachute.

The parachutist slows down.

Explain the change in speed of the parachutist.

Use ideas about forces in your answer.

It is observed that from when the parachute opens to just before the parachutist touches the ground, the GPE store and the KE store of the parachutist both decrease, yet energy is still conserved.

Justify these observations.

A person throws an object vertically upwards.

The speed-time graph shows how the speed of the object varies from the time it is thrown until reaching its maximum height.

Calculate the acceleration of the object.

acceleration =_........ m / s²

Calculate the distance the object travels to reach its maximum height.

A different object is dropped from rest and begins to fall.

The graph shows how the speed of this object varies with time.

Give the name of the two forces acting on the object as it falls.

Draw arrows on the diagram to show the forces acting on the object at B.

Explain the shape of the graph from A to C.

You should use ideas about forces to help your answer.

The diagram shows a ball at the bottom of a ramp. The ball moves up the ramp with an initial speed v.

State the formula linking gravitational potential energy (GPE), mass, gravitational field strength (g) and height.

The ball has a mass of 14 g.

Show that when the ball reaches a height of 29 cm above the bottom of the ramp, the GPE gained by the ball is about 4 10⁻²J.

At the bottom of the ramp, the 14 g ball has a kinetic energy (KE) of 5.1 10⁻²J.

Calculate the speed of the ball at the bottom of the ramp.

The ball is stationary when it reaches the top of the ramp. There is a difference between the KE of the ball at the bottom of the ramp and the GPE of the ball at a height of 29 cm above the bottom of the ramp.

Explain why the work done by friction between the ball and the ramp is equal to this difference.

A glass contains fizzy water.

Bubbles of carbon dioxide form at the bottom of the glass and rise to the surface.

The graph shows the relationship between the volume of a bubble and the pressure of the gas in the bubble.

Describe the relationship shown by the graph.

State the formula linking pressure difference, height, gravitational field strength and density.

The depth of the fizzy water in the glass is 22 cm.

The density of the fizzy water is 1080 kg/m³.

Calculate the pressure difference at the bottom of the glass due to the fizzy water.

Calculate the pressure of the gas in the bubble when the bubble is at the bottom of the glass.

[atmospheric pressure = 101 000 Pa]

When a bubble is at the top of the glass, the pressure of the gas in the bubble is equal to 101 000 Pa and the bubble has a volume of 0.084 cm³.

Calculate the volume of the gas in the bubble when the bubble is at the bottom of the glass.

Assume the temperature of the gas remains constant.

volume =_........ ³

A force called upthrust acts vertically upwards on the bubble.

When the bubble is released, it accelerates vertically upwards.

Draw two labelled arrows on the diagram to show the forces on the bubble as it is released.

A student uses this apparatus to investigate the force needed to pull a block along a ramp.

State the formula linking work done, force and distance moved in the direction of the force.

The student pulls the block 0.89 m along the ramp with a force of 26 N.

Show that the work done on the block by the 26 N force is about 23 J.

The block has a mass of 1.3 kg and moves vertically upwards 0.11 m.

Calculate the increase in the gravitational potential energy (GPE) store of the block between the bottom and the top of the ramp.

Explain why the work done to move the block along the ramp is greater than the increase in the GPE store of the block.

The student suggests it is better to use a less steep ramp to raise the block through the same vertical height.

Discuss an advantage and a disadvantage of using a less steep ramp.

State Hooke’s Law.

The graph shows how the extension of a rubber band varies with the force applied.

Explain how the graph shows that the rubber band does not obey Hooke’s Law.

Diagram 1 shows a model aeroplane powered by a rubber band.

A person rotates the propeller of the model aeroplane, which twists the rubber band.

He then releases the propeller and it spins.

Energy transfer occurs during this process.

The box lists words associated with energy.

Use words from the box to complete the passage.

The person does_........ work to twist the rubber band.

As the person twists the rubber band it extends, increasing the_........

energy store of the rubber band. When the rubber band is released it does mechanical work,

increasing the_........ energy store of the propeller.

Diagram 2 shows the aeroplane flying horizontally to the right.

Diagram 2

The aeroplane flies at a constant speed.

Diagram 2 shows two forces acting on the aeroplane.

Draw labelled arrows on diagram 2 to show two more forces acting on the aeroplane.

A student investigates how the surface material of a ramp affects the average speed of a block sliding down the ramp.

Design a suitable method for the student’s investigation.

Your answer should include

● the measuring equipment needed

● details of the independent, dependent and control variables

● how the average speed will be determined

You may include a diagram to help your answer.

Justify why the student should display their results as a bar chart.

The graph shows how the velocity of a parachute jumper changes with time.

At point A, the parachute jumper is falling at terminal velocity and has not yet opened her parachute.

Which statement is correct about the parachute jumper at point A?

Which is the best estimate of the distance fallen by the parachute jumper from the start until point A?

The parachute jumper opens her parachute at point B.

Her velocity decreases until she reaches terminal velocity again at point C.

Explain this change in velocity.

After point C, the parachute jumper continues to fall at a constant velocity.

As she falls, energy is transferred from a gravitational store.

Which store is the energy transferred into?

Diagram 1 shows a van accelerating along a horizontal road.

The horizontal forces acting on the van are shown.

Force X opposes the motion of the van.

State the name of force X.

The resultant force acting on the van is 1500 N.

Calculate the magnitude of force X.

[assume X is the only horizontal force opposing the motion of the van]

Diagram 2 shows the resultant force acting on the van when it brakes.

State the formula linking resultant force, mass and acceleration.

The mass of the van is 1900 kg.

Calculate the acceleration of the van when it brakes.

Give the unit.

The van was travelling at an initial speed of 18 m/s before braking and coming to rest.

Calculate the distance travelled by the van while it is braking.

[assume that the acceleration remains constant]

Describe two factors that would increase the braking distance.

When the van is fully loaded its mass increases to 2500 kg.

Calculate the time taken to bring the fully loaded van to rest when it is travelling at an initial speed of 18 m/s.

[assume that the resultant force during braking remains at 14 kN]

This is a question about alpha particles.

Describe the nature of an alpha particle.

The diagram shows the path of an alpha particle as it passes close to a nucleus.

Draw an arrow from point X to show the force on the alpha particle due to the nucleus.

Label this force Y.

Draw an arrow to show the force on the nucleus due to the alpha particle.

Label this force Z.

Explain how the path of the alpha particle shows whether the nucleus is positive, negative or neutral.

The alpha particle experiences a resultant force of 3.6 N and has a mass of 6.610^–27kg.

Calculate the acceleration of the alpha particle.