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प्रश्न
State the principle of moments.
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उत्तर
Principle of moments: If a body is in equilibrium under the action of number of force, then the sum of clockwise moments is equal to the sum of anticlockwise moments.
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संबंधित प्रश्न
State two factors on which power spent by a source depends. Explain your answer with examples.
A boy weighing 350 N climbs up 30 steps, each 20 cm high in 1 minute, Calculate:
- the work done and
- power spent.
An ox can apply a maximum force of 1000 N. It is taking part in a cart race and is able to pull the cart at a constant speed of 30 ms-1 while making its best effort. Calculate the power developed by the ox.
A body of mass m is moving with a uniform velocity u. A force is applied on the body due to which its velocity changes from u to v. How much work is being done by the force?
The moment of a force 10 N about a point 0 is 4 Nm. Calculate the distance of point of application of force from the point 0.
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.
A force of 1 kgf displaces a body by a distance of 10 cm
(i) in direction of force,
(ii) normal to the force
(iii) at an angle of 60° to the direction of the force.
Calculate the amount of work done in each case. (Take: g = 9.8 ms−2 )
For the following scenario, state whether the work done by gravity is positive, negative, or zero.
A person walks on a levelled road.
