BECE Science 2023 Paper

Concept:Gravitational potential energy is the energy a body has because of its height above the ground. Lifting a body through a height $h$ stores energy equal to the work done against its weight $mg$.Formula used:$PE = mgh$, where $m$ = mass, $g$ = acceleration due to gravity, $h$ = heightGiven:$m = 70 \text{ kg}$$g = 10 \text{ m s}^{-2}$$h = 15 \text{ m}$Solution:Weight of the pupil: $mg = 70 \times 10 = 700 \text{ N}$$PE = mgh = 700 \times 15$$700 \times 15 = 10{,}500$So $PE = 10{,}500 \text{ J}$ (since $1 \text{ N} \times 1 \text{ m} = 1 \text{ J}$).Key point: Option D ($700$) is only the weight in newtons; it must still be multiplied by the height.Answer:Option A ($10{,}500 \text{ J}$)