Power

Question 1

What is power

Answer 1

Power is the rate of energy transfer

Question 2

State the equation for power

Answer 2

Power = energy transferred ÷ time taken
P = E ÷ t
(Watts) (Joules) (seconds)

Question 3

One exercise that Tyron does is called a ‘lateral raise’. He lifts a 20N dumbbell up to shoulder height.
(i) Calculate the work done on the dumbbell jn one lateral raise (2 marks)
(ii) The dumbbell is lifted 15 times in 1 minute. Calculate the power (3 marks)

Answer 3

(i) E W = F x s
U 50cm = 0.5
S W = 20 x 0.5
A ✔️
C 10J
(ii) E P = E ÷ t
U 1 minute = 60 seconds
S P = 150 ÷ 60
A ✔️
C 2.5W

Question 4

Energy transferred = work done so:

Answer 4

Power = work done ÷ time taken