Chapter 6, Problem 57A

(a)

To determine

Thedirection of a force act on the yo-yo which whirlsabout a head in horizontal circle.

Explanation of Solution

Introduction:

Whenever object revolves in circular motion at constant speed, the net force is acting on a object that acts towards the center of the circle. This force is centripetal force.

From the given information, it is seen that yo-yo whirls in circular motion and in circular motion object remains in circular motion due to centripetal force which is actingtowards the center of the motion. Thus, force acting on the yo-yo is along the string and toward the center of a circle.

Conclusion:

The force acting on the yo-yo is along the string and toward the center of a circle.

(b)

To determine

The element that exerts force on the yo-yo which whirls about a head in horizontal circle.

Explanation of Solution

Introduction:

Whenever object revolves in circular motion at constant speed, the net force is acting on a object that acts towards the center of the circle. This force is centripetal force.

From the given information, it is seen that yo-yo whirls in circular motion and the string exerts a force on yo-yo.

Conclusion:

String exerts a force.

(c)

To determine

The direction in which yo-yo travel using Newton's laws of motion.

Explanation of Solution

Introduction:

Newton's first law of motion is about law of inertia. It is stated as every object remains in state of rest or in motion unless external force applied on it.

Newton's second law is of momentum. It is stated as the acceleration of an object produced by the total force is directly proportional to the force.

First the velocity of the yo-yo will not change when the string is released.

Here object motion not changed this is Newton's first law of motion.

As yo-yo is moving in circular motion gravitational force acting on the yo-yo.

So, byNewton's second law of motion the downward acceleration on the toy which acts as a projectile motion in horizontal direction.

Conclusion:

The toy acts as a projectile motion in horizontal motion.