Advertisements
Advertisements
प्रश्न
A woman pulls a bucket of water of total mass 5 kg from a well which is 10 s. calculate the power used by her.
Advertisements
उत्तर
Given mass = 5kg, height = 10m, time = 10s
Power = `"mgh"/"t" = (5 xx 10 xx 10)/10` 50 watt
APPEARS IN
संबंधित प्रश्न
A machine raises a load of 750 N through a height of 16 m in 5 s. calculate:
- energy spent by machine,
- power at which the machine works.
MULTIPLE CHOICE TYPE
In an electric cell which in use, the change in energy is from:
A boy weighing 25 kgf climbs up from the first floor at height 3 m above the ground to the third floor at height 9m above the ground. What will be the increase in his gravitational potential energy? (Take g = 10 N kg -1)
State the SI unit of work.
Explain by an example that a body may possess energy even when it is not in motion.
When do we say that work is done? Write the formula for the work done by a body in moving up against gravity. Give the meaning of each symbol which occurs in it.
Calculate the work done when:
A 5 kg weight is lifted 10 m vertically. (g = 9.8 m/s2)
Look at the activity below. Reason out whether or not work is done in the light of your understanding of the term ‘work’.
A donkey is carrying a load on its back.
A force of F = (5y + 20) `hat"j"` N acts on a particle. The work done by this force when the particle is moved from y = 0 m to y = 10 m is ______ J.
