Advertisements
Advertisements
Question
Give scientific reasons.
It is easier to stop a tennis ball as compared to a cricket ball when both are travelling with the same velocity.
Advertisements
Solution
- The momentum of a body is the product of its mass and velocity, i.e., p = mv and the rate of change of momentum of a body is equal to the force applied, i.e., `"F" = ("m"("v" -"u"))/"t"`.
- In the given information, both the balls move with the same velocity and finally stop; thus, the force applied to stop the ball will be directly proportional to the mass of the ball.
F ∝ m - It is easier to stop a tennis ball than a cricket ball moving with the same speed because the momentum of a cricket ball will be higher than that of the tennis ball, as the mass of the cricket ball is more than tennis ball. Therefore, less force is required to stop the tennis ball when compared to the cricket ball.
APPEARS IN
RELATED QUESTIONS
If action is always equal to the reaction, explain how a horse can pull a cart.
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?
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.
Is the following statement true or false :
A rocket can propel itself in a vacuum.
What is the force which produces an acceleration of 1 m /s2 in a body of mass 1 kg ?
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 ?
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 ?
Draw a diagram to show how a rocket engine provides a force to move the rocket upwards. Label the diagram appropriately.
State Newton’s third law of motion and give two examples to illustrate the law.
Explain why, when a fireman directs a powerful stream of water on a fire from a hose pipe, the hose pipe tends to go backward.
According to the third law of motion, action and reaction :
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.
Why do the action and reaction forces in a pair not cancel each other out?
In a hose pipe ejecting water, what is the reaction force?
What is the main characteristic of action and reaction forces?
