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प्रश्न
उत्तर
The work done by the gravitational force of the earth on a satellite revolving around the earth is zero because the motion of the satellite is perpendicular to the force at every point.
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संबंधित प्रश्न
Power spent by a body depends on the time for which it does work.
.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.
A box of weight 150 kgf has gravitational potential energy stored in it equal to 14700 J. Find the height of the box above the ground. (Take g = 9.8 N kg-1)
Write the formula for work done on a body when the body moves at an angle to the direction of force. Give the meaning of each symbol used.
The work done by a force acting obliquely is given by the formula : W = F cos θ ✕ s. What will happen to the work done if angle θ between the direction of force and motion of the body is increased gradually? Will it increase, decrease or remain constant.
How much work is done by the gravitational force of earth acting on a satellite moving around it in a circular path? Give reason for your answer.
The work done on an object does not depend on the :
Distinguish between work and power.
Name the physical quantity associated with the 'rate of doing work'.
An electric motor drives a machine which lifts a mass of 4 kg through a height of 10 m in 5 s at a constant speed. Assuming g = 10 ms-2, calculate
(i) the amount of work done, (ii) the power of the machine.
Fill in the boxe to show the corresponding energy transformation.
Give an example
Light energy changes to electrical energy.
Is power a scalar or a vector quantity?
What do you understand by the term energy? Is energy a scalar or vector? How is the energy possessed by a body measured?
What is the difference between renewable and non-renewable resources?
Write the two main conditions are needed for work to be done?
Look at the activity below. Reason out whether or not work is done in the light of your understanding of the term ‘work’.
An engine is pulling a train.
