A ball is projected upward at time t = 0 s,from a point on a flat roof 10 m above the ground.The ball rises and then falls with insignificant air resistance,missing the roof,and strikes the ground.The initial velocity of the ball is 58.5 m/s. Consider all quantities as positive in the upward direction.At time t= 5.97 s, The vertical velocity of the ball is closest to
A)0 m/s.
B)+175 m/s.
C)+12 m/s.
D)-175 m/s.
E)-12 m/s.

Question

A ball is projected upward at time t = 0 s,from a point on a flat roof 10 m above the ground.The ball rises and then falls with insignificant air resistance,missing the roof,and strikes the ground.The initial velocity of the ball is 58.5 m/s.  Consider all quantities as positive in the upward direction.At time t= 5.97 s, The vertical velocity of the ball is closest to
A)0 m/s.
B)+175 m/s.
C)+12 m/s.
D)-175 m/s.
E)-12 m/s.

Quizplus · Accepted Answer

At the highest point of the trajectory, the vertical velocity of the ball is zero.

A Ball Is Projected Upward at Time T = 0