Short Answer Typei) What are non-contact force?
ii) How does the distance of separation between two bodies affect the magnitude of the non-contact force between them?A boy of mass 30 kg is sitting at a distance of 2 m from the middle of as ea-saw. Where should a boy of mass 40 kg sit so as to balance the sea-saw?
Let the boy of mass 40 kg is sitting at a distance of x m from the middle of the see-saw on other side of the boy of mass 30 kg to balance the see-saw.
Now, using principle of moments, 
i) What is meant by the term ‘moment of force’?
ii) If the moment of force is assigned a negative sign then will the turning tendency of the force be clockwise or anti-clockwise?
i) Which of the following remains constant in uniform circular motion: Speed or velocity or both?
ii) Name the force required for uniform circular motion. State its direction.A ball is placed on a compressed spring. When the spring is released, the ball is observed to fly away.
i) What form of energy does the compressed spring possess?
ii) Why does the ball fly away?i) State the energy conversion taking place in a solar cell?
ii) Give one disadvantage of using a solar cellA body of mass 0.2 kg falls from a height of 10 m to a height of 6 m above the ground. Find the loss in Potential energy taking place in the body.
State the class of levers and the relative positions of load (L), effort (E) and fulcrum (F) in each of the following cases:
1. A bottle opener
2. Sugar tongs
Why is less effort needed to lift a load over an inclined plane as compared to lifting the load directly?
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