A ball is spun in a circle with constant speed, parallel to the ground. Ifthe center of the circle is kept at the same height but the circle of motionchanged to be perpendicular to the ground and keeping the same speed, waswork done on the ball?
If it kept the same speed, then work = m g *diameter had to be done to reach the top from the bottom of the circle.
By the way in real life the thing would slow down a little on the way up.
To determine if work is done on the ball, we need to consider the definition of work. Work is done when a force is applied over a distance and there is a transfer of energy. In this case, we can examine the forces acting on the ball in both scenarios.
When the ball is spun in a circle with constant speed parallel to the ground, the force acting on it is directed towards the center of the circle. This force, known as the centripetal force, keeps the ball moving in a circular path. Since the displacement of the ball is perpendicular to the force, no work is done on the ball in this scenario.
Now, let's consider the case where the circle of motion is changed to be perpendicular to the ground while keeping the same speed. In this scenario, the ball will experience a different force called the normal force. The normal force is the force exerted by the ground perpendicular to the surface on which the ball is rolling.
As the ball moves in a circle perpendicular to the ground, the normal force acts towards the center of the circle, just like the centripetal force in the previous scenario. Once again, the displacement of the ball is perpendicular to the force, meaning no work is done on the ball in this case as well.
Therefore, in both scenarios, no work is done on the ball. The forces acting on the ball are perpendicular to the displacement, and as a result, there is no transfer of energy.