Changes in energy

MS 3b, c

Students should be able to recall and apply this equation.

The amount of elastic potential energy stored in a stretched spring can be calculated using the equation:

$$\textit{elastic potential energy} = 0.5 \times \text{spring constant} \times (\text{extension})^2$$ $$[E_e = \frac{1}{2}ke^2]$$

(assuming the limit of proportionality has not been exceeded)

elastic potential energy, Eₑ, in joules, J

spring constant, k, in newtons per metre, N/m

extension, e, in metres, m

MS 3b, c

Students should be able to apply this equation which is given on the Physics equation sheet.

The amount of gravitational potential energy gained by an object raised above ground level can be calculated using the equation:

$$g.p.e. = \text{mass} \times \text{gravitational field strength} \times \text{height}$$ $$[E_p = mgh]$$

gravitational potential energy, Eₚ, in joules, J

mass, m, in kilograms, kg

gravitational field strength, g, in newtons per kilogram, N/kg (In any calculation the value of the gravitational field strength will be given).

height, h, in metres, m

MS 3b, c

Students should be able to recall and apply this equation.

AT 1

Investigate the transfer of energy from a gravitational potential energy store to a kinetic energy store.