Advertisements
Advertisements
प्रश्न
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. Compare:
- the work done, and
- the power developed by them. Take g = 10 N kg-1
Advertisements
उत्तर
Mass of box m = 50 kg
Height to which box is raised h = 2m
(i) Work done by each man = mgh
= 50 × 10 × 2
= 1000 J
∵ Work done is independent of time taken
∴ Ratio of work done = 1 : 1
(ii) `"Power in first case"/"Power in second case" = (w/t_1)/(w/t_2)`
= `(1000/(20 s))/(1000/(50 s))`
= `50/20`
= 5 : 2
APPEARS IN
संबंधित प्रश्न
State and define the S.I. unit of work.
One horse power is equal to ______.
Work is a scalar quantity because it is a measure of transfer of energy without indicating any direction
A boy takes 3 minutes to lift a 20 litre water bucket from a 20 m deep well, while his father does it in 2 minutes. Compare:
- the work, and
- power developed by them.
A bullet fired against a window glass pane makes a hole in it without any cracks while a stone striking the same glass pane smashes it; explain with reason.
State the condition when the work done by the force is positive
State the condition when the work done by the force is negative.
What happens to the power if the time for doing work is reduced from t second to t/10 second?
State the C.G.S. unit of work. How it is related to its S.I. unit?
