Forces and elasticity

A metal spring obeys Hooke’s law.

Sketch a graph to show that the spring obeys Hooke’s law as it is stretched.

You should label both axes with appropriate physical quantities.

Diagram 1 shows an object suspended from a support using a metal spring.

The object is initially at rest.

The object is pulled down and then released.

Diagram 2 shows the forces acting on the object at the instant it is released.

Determine the magnitude and direction of the resultant force acting on the object.

The object has a mass of 0.20 kg.

Calculate the acceleration of the object at the instant it is released.

acceleration =_........ ²

Explain how the magnitude of the acceleration of the object changes, from the instant the object is released until the first time the object returns to its initial resting position.

You should refer to the forces acting on the object in your answer.

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

Diagram 1 shows a set of masses attached to a spring, which is suspended from a support.

After the masses are added, the length of the spring is 14.6 cm.

The student measures the extension of the spring as 11.5 cm.

Calculate the original length of the spring.

The student removes the masses and notices that the spring does not show elastic behaviour.

Predict a value for the new length of the spring after the masses have been removed.

The student puts the masses back on the spring.

The student then pulls the masses down and releases them.

The masses vibrate up and down in a vertical direction, as shown in diagram 2.

The distance–time graph shows how the distance between the top of the masses and the support changes with time as the masses vibrate.

Explain how the gradient of the graph shows that the masses accelerate as they vibrate.

Add crosses (X) to the distance–time graph to show all the times when the masses are not moving.

A material is stretched by applying an increasing load. The material shows elastic behaviour as it is stretched.

Describe what is meant by elastic behaviour.

The material obeys Hooke’s law.

Sketch a graph for this material to show that it obeys Hooke’s law as it is stretched.

You should label both axes with appropriate physical quantities.

Diagram 1 shows a gate fitted with a spring mechanism.

The spring mechanism shuts the gate automatically.

The graph shows some data from an investigation into how the extension of the spring changes with an increasing force.

Describe the relationship shown by the graph.

Diagram 2 shows the gate viewed from above.

The force the spring exerts on the gate is 480 N.

Show that the moment of the force the spring exerts on the gate is about 400 Nm.

The force, F, is the minimum force needed to start opening the gate.

Calculate the magnitude of force F.

The spring is removed for testing.

Explain what will happen to the spring if the force applied to extend the spring is too large.

A student investigates how the extension of a spring varies when the mass attached to the spring is changed.

The diagram shows most of the equipment the student uses in the investigation.

Describe a method the student could use for the investigation.

Your description should include the measurements taken and how the student could obtain accurate results.

The student calculates the force each mass applies to the spring.

The table shows the student’s results.

Plot the student’s results.

Draw a circle around the anomalous point.

Draw a line of best fit.

Explain whether the spring obeys Hooke’s Law.

A student uses this apparatus to investigate the stretching of a rubber band.

This is the student’s method.

● attach the 12 cm long rubber band to a clamp stand

● hang a 1 N weight from the other end of the rubber band

● determine the extension of the rubber band

The student repeats this method, increasing the weight by 1 N each time until the weight is 10 N.

Describe how the student could determine the extension of the rubber band.

The graph shows the student’s results.

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

The area under the curve on the graph is equal to the increase in the rubber band’s elastic energy store.

Estimate the increase in the rubber band’s elastic energy store when the rubber band has been extended by 20 cm.

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.

The line has a straight section and a curved section.