Question

During an interval of time, a tennis ball is moved so that the angle between the velocity and the acceleration of the ball is kept at a constant 120º. Which statement is true about the tennis ball during this interval of time? 

(A) Its speed increases and it is changing its direction of travel.

(B) Its speed decreases and it is changing its direction of travel.

(C) Its speed remains constant, but it is changing its direction of travel.

(D) Its speed remains constant and it is not changing its direction of travel. 

(E) Its speed decreases and it is not changing its direction of travel. 

Answer 1

Correct option (B) Its speed decreases and it is changing its direction of travel.

At an angle of 120º, there is a component of the acceleration perpendicular to the velocity causing the direction to change and a component in the opposite direction of the velocity, causing it to slow down.