A rock is projected upward from the surface of the Moon,at time t = 0 s,with an upward velocity of 30.0 m/s.The acceleration due to gravity at the surface of the Moon is 1.62 m/s²,and the Moon has no atmosphere.The height of the rock when it is descending with a speed of 20.0 m/s is closest to A)115 m. B)125 m. C)135 m. D)145 m. E)154 m.

Question

Quizplus · Accepted Answer

We can use the kinematic equation:

v_f^2 = v_i^2 + 2ad

where v_f is the final velocity (20.0 m/s), v_i is the initial velocity (30.0 m/s), a is the acceleration due to gravity on the Moon (-1.62 m/s^2), and d is the distance traveled.

Solving for d, we get:

d = (v_f^2 - v_i^2)/(2a)
  = (20.0^2 - 30.0^2)/(2*(-1.62))
  = 154.32 m

Therefore, the height of the rock when it is descending with a speed of 20.0 m/s is closest to 154 m. The best choice is E.

A Rock Is Projected Upward from the Surface of the Moon,at