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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
If action is always equal to the reaction, explain how a horse can pull a cart.
Using a horizontal force of 200 N, we intend to move a wooden cabinet across a floor at a constant velocity. What is the friction force that will be exerted on the cabinet?
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.
A girl weighing 25 kg stands on the tloor. She exerts a downward force of 250 N on the floor. What force does the floor exert on her ?
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 ?
Why is it difficult to walk on a slippery road ?
Give a scientific reason.
Even though the magnitudes of action force and reaction forces are equal and their directions are opposite, their effects do not get cancelled.
“Wearing helmet and fastening the seat belt is highly recommended for safe journey” Justify your answer using Newton’s laws of motion.
According to the third law of motion, action and reaction
Consider a frame that is made up of two thin massless rods AB and AC as shown in the figure. A vertical force `vec"P"` of magnitude 100 N is applied at point A of the frame.
Suppose the force is `vec"P"` resolved parallel to the arms AB and AC of the frame.
The magnitude of the resolved component along the arm AC is xN.
The value of x, to the nearest integer, is ______.
[Given: sin(35°) = 0.573, cos(35°) = 0.819, sin(110°) = 0.939, cos(110°) = –0.342]
