Calculating the energy of springs (E = 1/2 kx²) | Starter Quiz | Oak National Academy

Which of the following describe work done?

• work done = force × distance moved in direction of force

• work done = force ÷ distance moved in direction of force

• work done = amount of force used

• work done = amount of energy transferred

Answer explanation

Work done is the amount of energy transferred when a force makes an object move. Work done equals the force multiplied by the distance moved in the direction of the force.

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

• 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.

Answer explanation

The force is directly proportional to the extension (as long as the spring is not stretched beyond its limit of proportionality). So the greater the extension, the greater the force needed to produce it.

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

• 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 is a unit of energy?

• watts

• joules

• newtons

• degrees Celsius

Answer explanation

Joules (J) is the unit of energy, watts (W) is the unit of power, newtons (N) is the unit of force and degrees Celsius (°C) is a unit of temperature.

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?

• Spring A has a higher spring constant than spring B.

• Spring B has a higher spring constant than spring A.

• Spring A is stiffer than spring B.

• Spring B is stiffer than spring A.

Answer explanation

Equal forces make spring A stretch more than spring B, so spring A is easier to stretch and spring B is stiffer. Spring constant is a measure of stiffness, so B has a higher spring constant.