If an elastic object is stretched, compressed or bent out of shape, there is energy in the elastic store.

To make something smaller using forces, e.g. a spring gets shorter when it is compressed.

The increase in length from the original length of a spring when it is stretched.

A measure of how stiff a spring is and how hard it is to stretch or compress.

Calculating the energy of springs (E = 1/2 kx²)

Combined science

In the Forces make things change unit, they will build on this knowledge to learn how to combine forces in two dimensions, how to calculate acceleration from a resultant force and how to calculate forces in collisions and explosions.

In the Measuring and calculating motion unit, pupils learnt how to measure and calculate velocity and acceleration, and how to interpret displacement-time and velocity-time graphs. 

Energy of moving objects

Which of the following words means ‘make something smaller using forces’?

The spring is stretched from 10 cm to 12 cm long.

The spring is stretched from 15 cm to 17 cm long.

The spring is stretched from 15 cm to 18 cm long.

The spring is stretched from 10 cm to 18 cm long.

A spring has a length of 10 cm. Starting with the least energy transferred to the elastic store, sort the following deformations into order of increasing energy.

A pupil stretches a spring. The work done by the pupil is equal to …

A spring of length 6.0 cm has spring constant 960 N/m. How much energy does it gain if it is stretched to 8.0 cm?

A spring is stretched by 4.0 cm, transferring 96 J of energy to the elastic store.
What is the spring constant of the spring?

A spring has spring constant 2000 N/m. The spring is stretched, transferring 250 J of energy to the elastic store. What is the extension of the spring?

work done = force × distance moved in direction of force

work done = force ÷ distance moved in direction of force

Which of the following describe work done?

The size of the force increases as the extension increases.

The size of the force decreases as the extension increases.

The size of the force stays the same as the extension increases.

A pupil stretches a spring. Which of the following statements is correct?

It is a measure of how stiff a spring is.

It is the length of a spring when it is stretched.

It is the amount of force per metre of extension.

It is the amount of extension per newton of force.

Which of the following can be used to describe the spring constant of a spring?

Which of the following is a unit of energy?

Spring A has a higher spring constant than spring B.

Spring B has a higher spring constant than spring A.

Two springs, A and B, are equal in length. Identical masses are hung from the springs which do not stretch beyond their limits of proportionality.
Which of the following statements are correct?

Square $$v$$, then multiply by $$m$$, then divide by 2.

Divide $$m$$ by 2, then multiply by $$v$$, then square.

Multiply $$m$$ by $$v$$, then square, then multiply by ½ .

Square $$v$$, then multiply by ½, then multiply by $$m$$.

A pupil wants to calculate a kinetic energy using the formula: kinetic energy = $$\frac{1}{2}mv^2$$. Which of the following calculations will give them the correct answer?

Introduction

What will you need for this lesson?

Are you ready to learn?

Equipment

Worksheet