Answer
In the case of uniform velocity, the net force on the ball is zero. The tension force pulling up on the ball is equal in magnitude to the weight of the ball directed down. Therefore, the net force on the ball is zero and the acceleration is zero.
In the case of uniform acceleration, there is a net horizontal force directed to the right. This is the horizontal component of the tension in the string, which accelerates the ball to the right.
Work Step by Step
In the case of uniform velocity, the net force on the ball is zero. The tension force pulling up on the ball is equal in magnitude to the weight of the ball directed down. Therefore, the net force on the ball is zero and the acceleration is zero.
In the case of uniform acceleration, there is a net horizontal force directed to the right. This is the horizontal component of the tension in the string, which accelerates the ball to the right.
