Question

If the man lifts a load up with the help of a rope such that it raises the load of mass 50kg to a height of 20 m in 100 second. Find the power of man

Answer 1

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

Work Done (W) = Force × Displacement

                          = Mass × Acceleration due to gravity × Displacement

                          = 50 × 10 × 20

                          = 10000 J

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

                                      = $\frac{10000}{100}$

                                      = 100 W

Hence, the power of man is 100 W.

Answer 2

Answer:

The power of the man is 100 Watt.

Explanation:

Here we have been given that a man has lifted a load up with the help of a strong rope such that it raises the load which has a mass of 50 kg to a height of 20 m. He has done it in 100 seconds. We have to find the power of man. Now as we know that power is the ratio of the work that is done and the total time that was taken to do it.

So we have,

Mass of the load (m) = 50 kg

Height (h) = 20 m

Acceleration due to the gravity (g) = 10 $ms^{-2}$

Time taken (t) = 100 seconds

Now we know that:

Power (P) = Workdone (W) / Time (t)

We know that work done here is equal to the potential energy that is being stored in the load when carried to the height of 20m.

Therefore, W = mgh

⇒ P = mgh / t

⇒ P = $\frac{50 kg (10ms^{-2})(20m) }{100 sec}$

⇒ P = 100 W

It has been found that the power of man is 100 W.