A man raises a box of mass 50 kg to a height of 2 m in 20 s, while another man raises the same box to the same height in 50 s.

(a) Compare:(i) the work done,and (ii) the power developed by them.

(b) Calculate:(i) the work done,and (ii) the power developed by each man.Take g=10 N $k g^{- 1}$ .

Open in App

Solution

Both men are raising mass 50kg to a height of 2m.
Work done by first man = mgh
=50102
= 1000 J

Work done 2nd man = mgh
=50102
= 1000 J

1st man picks up in 20 sec so power developed by 1st man = $fraction numerator w o r k over denominator t i m e end fraction$
= $\frac{1000}{20}$
= 50 Watt

2nd man picks up in 50 sec so power developed by 2nd man = $fraction numerator w o r k over denominator t i m e end fraction$
= $\frac{1000}{50}$
= 20 Watt

∴ Work done by both of them is same, but power developed by them is 50 Watt and 20 Watt respectively.

Suggest Corrections

Similar questions

Q. A man raises a box of mass

50 k g

to a height of

2 m

2

minutes, while another man raises the same box to the same height in

5

minutes. Ratio of the power developed by them:

Q. A man raises a box of mass

50 k g

to a height of

2 m

2 m i n u t e s

, while another man raises the same box to the same height in

5 m i n u t e s

. What is the ratio of work done by them ?

A weight lifter lifted a load of 200 kgf to a height of 2.5 m in 5 s. Calculate :(i) the work done, and (ii) the power developed by him.Take g=10 N $k g^{- 1}$ .

It takes 20 s for a person A of mass 50 kg to climb up the stairs, while another person B of same mass does the same in 15 s.Compare the (i) work done, and (ii) power developed by the persons A and B.

A man of mass 50 kg climbs up a ladder of height 10 m. Calculate:

(i) the work done by the man, and

(ii) the increase in his potential energy. (g = 9.8 m $s^{- 2}$ ).

Join BYJU'S Learning Program

Explore more

Power

Standard X Physics

Join BYJU'S Learning Program

A man raises a box of mass 50 kg to a height of 2 m in 20 s, while another man raises the same box to the same height in 50 s. (a) Compare:(i) the work done,and (ii) the power developed by them. (b) Calculate:(i) the work done,and (ii) the power developed by each man.Take g=10 N kg−1.

A man raises a box of mass 50 kg to a height of 2 m in 20 s, while another man raises the same box to the same height in 50 s.

(a) Compare:(i) the work done,and (ii) the power developed by them.

(b) Calculate:(i) the work done,and (ii) the power developed by each man.Take g=10 N $k g^{- 1}$ .