Advertisements
Advertisements
Question
A body does 1200 joules of work in 2 minutes. Calculate its power.
Advertisements
Solution
Work done (W) = 1200 J
Time taken (t) = 120 s
We can calculate the power of the body as,
Power = `"Work done"/"Time"`
So ,
Power = `1200/120` W
= 10 W
So, the power of this appliance is 10 W.
APPEARS IN
RELATED QUESTIONS
Define average power.
A person holds a bundle of hay over his head for 30 minutes and gets tired. Has he done some work or not? Justify your answer.
Calculate the work done by the brakes of a car of mass 1000 kg when its speed is reduced from 20 m/s to 10 m/s?
A body of mass 100 kg is lifted up by 10 m. Find :
(i) the amount of work done
(ii) potential energy of the body at that height (value of g = 10 m/s2)
How much is the mass of a man if he has to do 2500 joules of work in climbing a tree 5 m tall? (g = 10 m s−2)
What is the power of a body which is doing work at the rate of one joule per second?
A car of weight 20000 N climbs up a hill at a steady speed of 8 m/s, gaining a height of 120 m is 100 s. Calculate : work done by the car.
Define power. Give the SI unit of power.
A boy weighing 40 kg carries a box weighing 20 kg to the top of a building 15 m high in 25 seconds. Calculate the power. (g = 10 m/s2)
How is the power related to the speed at which a body can be lifted? How many kilograms will a man working at the power of 100 W, be able to lift at a constant speed of 1 m s–1 vertically? (g = 10 m s–2)
