Page 14 - TRIAL 2

b) Determine the power generated by Kevin 14. A boy lifts a bucket with 60N force in 1 minute
Zahri. out of a well. The bucket is lifted at 15m.

a) How much work is done on the bucket by
the boy?

11. A student of mass 58 kg runs up a flight of 25
steps, each of 20cm high. What is the power
generated by the boy if he takes 20s to climb to

the top of the stairs?

b) How much power is exerted by the boy?

12. A water pump is running at an efficiency of 80%
with power output 6kW to deliver clean water 15. An electric motor lifts an object of 250 kg to a
to water supply tank. Calculate the power input height of 210 meter in 28 second. If the input
of the water pump. power of the electric motor is 20000 W,
calculate the efficiency of the electric motor.

(Final Exam Session Dec 17)

13. If a 100W electric motor has an efficiency of

82%, find the time it takes to lift a 40kg object
to a height of 8.5m? 16. A squirrel with a mass of 2.5 kg is trying to jump
from a tree which is 3 meter high from the
ground. Calculate the potential energy and

kinetic energy based on the situations below:
(Final Exam Session Dec 17)

i. When the squirrel is still on the tree

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