Solve the problem.
-The acceleration of gravity near the surface of Mars is 3.72 m/sec2. If a rock is blasted straight up from the surface with an initial velocity of 85 m/sec (about 190 mph), how high does it go? (Hint: When is velocity zero?)
A) Approximately 1942.25 meters
B) Approximately 22.85 meters
C) Approximately 971.1 meters
D) Approximately 170 meters

Question

Quizplus · Accepted Answer

Using the kinematic equation v^2 = u^2 + 2as, where v = 0 m/sec (velocity when the rock reaches its highest point), u = 85 m/sec, a = -3.72 m/sec^2 (negative since the acceleration due to gravity acts in the opposite direction to the initial velocity), and solving for s (the height the rock reaches):
0^2 = 85^2 + 2(-3.72)s
0 = 7225 - 7.44s
s = 971.093 m
So, the rock reaches a height of approximately 971.1 meters. Therefore, the best choice is C.

Solve the Problem. -The Acceleration of Gravity near the Surface of Mars Is