Advertisements
Advertisements
प्रश्न
A man raises a box of mass 50 kg to a height of 2 m in 20s, while another man raises the same box to the same height in 50s. Calculated:
- the work done, and
- the power developed by each man. Take g = 10 N kg-1.
Advertisements
उत्तर
(i) Work done by each man = mgh
= 50 × 10 × 2
= 1000 J
(ii) Work done in first case = `w/t_1`
= `1000/20`
= 50 W
Work done in second case = `w/t_2`
= `1000/50`
= 20 W
APPEARS IN
संबंधित प्रश्न
A coolie X Carrying a load on his head climbs up a slope and another coolie Y carrying the identical load on his head move the same distance on a frictionless horizontal platform. Who does more work? Explain the reason.
Differentiate between work and power.
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.
State the practical unit mainly used in mechanical engineering and write down its equivalent in watt.
Relate 1 KWh (kilowatt hour) with joule.
A man weighing 700 N runs up a flight of 15 steps, each 20 cm high, in 5 seconds. Calculate the power of the man.
For the following scenario, state whether the work done by gravity is positive, negative, or zero.
A person climbs a ladder.
