Question

If a man lifts a load up with the help of a rope such that it raises the load of mass 50kg

to a height of 20m in 100 sec. Find the power of man
(class 9 science chapter work and energy extra question)​

Answer 1

Answer:

Given :

Mass (m) = 50 Kg

Height (H) 20 m

Time (T) = 100 second

To Find :

Power of the man

Solution :

Work done in unit time is called power.

Power = \frac{Work Done(W)}{Time(T)}

Time(T)

WorkDone(W)

Work Done (W) = Force × Displacement

= Mass × Acceleration due to gravity × Displacement

= 50 × 10 × 20

= 10000 J

∴ Power of the man (P) = \frac{Work Done (W)}{Time Taken (T)}

TimeTaken(T)

WorkDone(W)

={10000}{100} = 100 W

Hence, the power of man is 100 W.