Advertisements
Advertisements
प्रश्न
State two advantage of producing hydroelectricity.
उत्तर
Advantages of producing the hydroelectricity:
1. It does not produce any environmental pollution.
2. It is a renewable source of energy.
APPEARS IN
संबंधित प्रश्न
In each of the following a force, F is acting on an object of mass, m. The direction of displacement is from west to east, as shown by the longer arrow. Observe the diagrams carefully and state whether the work done by the force is negative, positive or zero.
No work is done by a force if the body
Give reasons for the following. No work is done if a man is pushing against a wall.
It takes 20 s for a person A of mass 50 kg to climb up the stairs, while another person B does the same in 15 s. Compare the Work done.
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.
Name the forms of energy which a wound-up watch spring possesses.
.A man raises a box of mass 50kg to a height of 2m in 20s, while another man raises the same box to the same height in 50s. Compare:
(i) the work done, and
(ii) the power developed by them.
The power of a motor is 40 kW. At what speed can the motor raise a load of 20,000 N?
How many watts equal one horse power?
A uniform circular motion is an accelerated motion. Justify it.
No work is done by a man moving on a horizontal road while carrying a box on his head. Explain.
A boy of mass m climbs up a staircase of vertical height h.
- What is the work done by the boy against the force of gravity?
- What would have been the work done if he uses a lift in climbing the same vertical height?
(a) Define power and name its unit.
(b) A girl weighting 50 kg climbs up 60 steps each of 20 cm height in 5 minutes. Calculate the power developed.
A girl of mass 50 kg runs up a flight of 40 steps in 20 seconds. If each step in 20 cm high, calculate the power developed by the girl. (g= 10 ms-2).
Fill in the boxe to show the corresponding energy transformation.
Fill in the boxe to show the corresponding energy transformation.
How long should an electric motor, of power 2 H.P. operate, so as to pump 5 m3 of water from a depth of 15m. [Take g = 10 N kg−1]
State whether work is done or not, by writing yes or no, in the following case:
A boy climbs up 20 stairs.
