Chapter 4, Problem 39A

To determine

To Explain: The speed of moving soccer ball decreased and it came to stop.

Explanation of Solution

Introduction:

According to Newton’s second law of motion, the force acting on the body is directly proportional to the change in the momentum with respect to time.

  $F=\frac{\Delta p}{\Delta t}$

Where, $\Delta p$ = change in momentum

  $\Delta t$ =time interval

In other words, the force is mathematically defined as it is product of mass and acceleration of the body.

  $F=ma$

Where. $m$ = mass of body

  $a$ = acceleration of body

Friction force is a type of force which always opposes the relative motion of object.

Initially, force is applied by the foot and because of that force, the ball starts moving and accelerates.

If there was no other force acting, then ball would have moved with constant acceleration but in the given situation, the speed of the ball decreases and it eventually stops moving.

There are other forces present to oppose the motion of ball. For example, friction force due to ground opposes the motion of the ball.Air will also apply the opposing force on the ball and its magnitude is directly proportional to the instantaneous velocity of ball. Because of these opposing forces, the ball will stop after some time.

Thus, it is not a correct statement that initially the force of the foot was transferred to ball and ball started moving and after some time,the force ran out and ball finally stopped. It is incorrect according to Newtonbecause force cannot be transferred, only energy can be transferred from one to another.