O-LevelPhysicsEnergy & Work5054/21 · Oct/Nov 2024 · Q28 Marks

A student makes a ball from modelling clay. The ball has a mass of 0.20 kg. She drops the ball from a height of 40 m above the ground.

(a)(i)Calculate the initial gravitational potential energy of the ball. gravitational potential energy = ................................................................. J [2][2]
(a)(ii)Calculate the speed of the ball immediately before the ball hits the ground. Ignore the effect of air resistance. speed = ................................................................. m/s [3][3]
(b)When the ball hits the ground, it stops moving. The kinetic energy of the ball is transferred to internal energy. The temperature of the ball increases.
(b)(i)The specific heat capacity of modelling clay is 1400J/(kg°C). Calculate the maximum possible temperature increase of the ball. Show your working. temperature increase = ................................................................. °C [2][2]
(b)(ii)Suggest one reason why the actual temperature increase of the ball may be smaller than the value calculated in (b)(i).[1]

Mark scheme

Marking points from the official mark scheme (Oct/Nov 2024). The mark or mark type is shown in brackets.

[C1] (G.P.E.=) mgh or 0.20 × 9.8 × 40
[A1] 78 (J)
[C1] (K.E. =) ½mv² or ½ x 0.2 × v²
[C1] (v =) √2gh or √2 × 9.8 × 40 or √784
[A1] 28 (m/s)
[C1] (∆θ =) ∆E / mc or 78.4 / (0.20 × 1400) or gh / c or 9.8 × 40 / 1400
[A1] 0.28 (°C)
[B1] some (thermal) energy is transferred to the ground or work is done deforming the modelling clay or air resistance / work done means that speed / k.e. is less than the calculated value

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