Advertisements
Advertisements
प्रश्न
Advertisements
उत्तर १
The law of conservation of energy states that energy cannot be created or destroyed; the sum total of energy in a closed system remains unchanged. Energy only changes from one form to another.
उत्तर २
According to the law of conservation of mechanical energy, the sum of kinetic energy and potential energy always remains constant.
APPEARS IN
संबंधित प्रश्न
A stone of mass m is rotated in a circular path with a uniform speed by tying a strong string with the help of your hand. Answer the following questions
1) Is the stone moving with a uniform or variable speed?
2) Is the stone moving with a uniform acceleration? In which direction does the acceleration act?
3) What kind of force acts on the hand and state its direction?
State the condition when the work done by a force is positive. Explain with the help of examples.
When a body moves in a circular path, how much work is done by the body? Give reason.
(Hint: The body is acted upon by the centripetal force.)
A body, when acted upon by a force of 10 kgf, gets displaced by 0.5 m. Calculate the work done by the force, when the displacement is (i) in the direction of force, (ii) at an angle of 60° with the force, and (iii) normal to the force. (g = 10 N kg-1)
Name the quality which is measured in kW.
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.
How is 1 kgf related to the SI unit of force?
In the following case write yes, if the work is being done and no if no work is being done.
A man trying to push a wall.
State two conditions for work to be done.
What is the S.I. unit of work? Define it.
