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प्रश्न
State Newton’s third law of motion and give two examples to illustrate the law.
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उत्तर
According to Newton’s third law of motion, whenever one body exerts a force on another body, the second body exerts an equal and opposite force on the first body.
Examples:
(i) Jet airplanes utilize the principle of action and reaction. In the modern jet aircraft, the hot gases obtained by the rapid burning of fuel rush out of a jet from the rear end of the aircraft at a great speed. The equal and opposite reaction of the backward-heading gases pushes the aircraft forward at a great speed.
(ii) While rowing a boat, the boatman pushes the water backwards with the oars. The water exerts an equal and opposite push on the boat which makes the boat move forward. In fact, harder the boatman pushes back the water with the oars, greater is the reaction force exerted by water and faster moves the boat, in forward direction.
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संबंधित प्रश्न
Explain, why is it difficult for a fireman to hold a hose, which ejects large amounts of water at a high velocity.
According to the third law of motion, when we push on an object, the object pushes back on us with an equal and opposite force. If the object is a massive truck parked along the roadside, it will probably not move. A student justifies this by answering that the two opposite and equal forces cancel each other. Comment on this logic and explain why the truck does not move.
If action is always equal to reaction, explain why a cart pulled by a horse can be moved.
Explain how a rocket works.
Do action and reaction act on the same body or different bodies ? How are they related in magnitude and direction ? Are they simultaneous or not ?
If a man jumps out from a boat, the boat moves backwards. Why ?
Explain why, a runner presses the ground with his feet before he starts his run.
Draw a diagram to show how a rocket engine provides a force to move the rocket upwards. Label the diagram appropriately.
According to the third law of motion, action and reaction :
While catching a cricket ball the fielder lowers his hands backwards. Why?
