288m ; [2] (ii) For how many seconds do the boys stay in the store? 240(s) ; S [1] (iii) Which boy slowed down on his way back to school? Explain your answer. boy C(no mark) (line on) graph goes down (so speed was changing)/owtte/use of data ; [1] 0654/31/M/J/13 Q6 An elephant of mass 5000kg exerts a constant force of 1400N to push a tree trunk along at a steady speed of 1.5m/s. Calculate the work done by the elephant when the tree trunk moves 10m. State the formula that you use and show your working. formula (W =) F × D orF × d orF × s ; working = 1400 × 10 = 14 000J ; __________________ [2] Calculate the kinetic energy of the elephant when it is moving at 1.5m/s. State the formula that you use and show your working. formula (KE =) ½ mv2; working = ½ × 5000 × 1.5 × 1.5 = 5625J ; __________________ [2]
288m ; [2] (ii) For how many seconds do the boys stay in the store? 240(s) ; S [1] (iii) Which boy slowed down on his way back to school? Explain your answer. boy C(no mark) (line on) graph goes down (so speed was changing)/owtte/use of data ; [1] 0654/31/M/J/13 Q6 An elephant of mass 5000kg exerts a constant force of 1400N to push a tree trunk along at a steady speed of 1.5m/s. Calculate the work done by the elephant when the tree trunk moves 10m. State the formula that you use and show your working. formula (W =) F × D orF × d orF × s ; working = 1400 × 10 = 14 000J ; __________________ [2] Calculate the kinetic energy of the elephant when it is moving at 1.5m/s. State the formula that you use and show your working. formula (KE =) ½ mv2; working = ½ × 5000 × 1.5 × 1.5 = 5625J ; __________________ [2]