Advertisements
Advertisements
प्रश्न
Explain why, a runner presses the ground with his feet before he starts his run.
Advertisements
उत्तर
A runner presses the ground with his feet before he starts his run to receive a large reaction force by the ground on which he exerts an action force, in the forward direction. In this way, he can gain a great speed.
APPEARS IN
संबंधित प्रश्न
A stone of 1 kg is thrown with a velocity of 20 m s−1 across the frozen surface of a lake and comes to rest after travelling a distance of 50 m. What is the force of friction between the stone and the ice?
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.
Why does a gunman get a jerk on firing a bullet ?
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.
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]
Why do the action and reaction forces in a pair not cancel each other out?
Can action and reaction forces be noncontact forces?
What is the main characteristic of action and reaction forces?
