Advertisements
Advertisements
प्रश्न
A man weighing 500 N carried a load of 100 N up a flight of stairs 4 m high in 5 seconds. What is the power?
Advertisements
उत्तर
Weight of the man, (W1) = 500 N
Weight of the load, (W2) = 100 N
Height, (h) = 4 m
Time taken, (t) = 5s
So total weight,
W = W1 + W2
= (500 + 100) N
= 600 N
We can calculate the work done against gravity as,Work done by the man is = (total weight)(vertical distance)
= (600)(4)
= 2400 J
Now, we can calculate the power of the man as,
Power = `"Work done"/"Time"`
So ,
Power = `2400/5` W
= 480 W
So , the power of man is 480 W .
APPEARS IN
संबंधित प्रश्न
What is power?
A battery lights a bulb. Describe the energy changes involved in the process.
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.
An electric heater is rated 1500 W. How much energy does it use in 10 hours?
A load of 100 kg is pulled up by 5 m. Calculate the work done. (g = 9.8 m/s2)
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)
Define kilowatt-hour.
Fill in the blank with suitable word :
Power is the rate of doing ___________.
Define power. Give the SI unit of power.
An electric motor raises a load of 0.2 kg, at a constant speed, through a vertical distance of 3.0 m in 2 s. If the acceleration of free fall is 10 m/s2, the power in W developed by the motor in raising the load is :
