Question

29. A man raises a box of 40 kg to a height of 5 m in
3 minutes while another man raises the same box
to the same height in 5 minutes. Compare the:
(a) work done
(b) power developed by them. ​

Answer 1

Answer:

a) work done by both of them will be same

b) power developed by 1st man is 11.1111 watt

power developed by 2nd man is 6.67 watt

Explanation:

work done = Force*Distance

where, Force is 40g, g=10m/second square or you can take 9.8 to be accurate

and distance is 5 metre.

since there is no entity of time in work done and it only depends on force and distance it is same for both mans.

work done by both man is 40*10*5=2000 joule.

b) power developed = work / time

power developed by 1st man is = 2000/ 180(3minutes=180 seconds)

power developed by first man = 2000/180=100/9=11.1111111

and power developed by second man is 2000/300= 20/3 = 6.67

Conclusion: work done by both man are same but power developed by the man who completed work fast is greater then the man the who completed the work late