Explain the following briefly:
(a) A cricket ball causes much severe injury than a tennis ball on hitting a spectator.
(b) An applied unbalanced force causes a change in momentum.
(c) A greater force is required to impart greater velocity to an object.
Answers
i am not able to understand the 2nd question.
Answer:
(a) A cricket ball has more mass than the tennis ball, so the momentum possessed by the Cricket ball will be more than tennis ball. As the momentum is more, change in momentum will be also more, so when the cricket ball hits the spectator, the final momentum becomes zero and hence the impact force of the cricket ball is more on hitting a spectator than tennis ball.
(b) When two or more forces which are unequal in magnitude are acting in the opposite direction of an object, which causes change in the state of motion are called as unbalanced forces. Unbalanced forces causes acceleration. If unbalanced forces are acting on an object, then the velocity of an object increases and hence its momentum also. Because momentum is defined as product of mass and velocity
(a) In order to change the velocity of the object you have to apply force. Because according to Newton first law of motion acceleration is directly proportional to the force and in order to change the acceleration you have to change the force. So, that’s mean you are changing the velocity too in order to create the acceleration as we know that the acceleration is produced by the change of velocity. This is why changing force mean changing the velocity too, greater the force greater will be the velocity.