Question

Special air bags are used to protect scientific equipment when a rover lands on the surface of Mars. On Earth, the function approximates an object's downward speed in feet per second as the object hits the ground after bouncing x ft in height. The corresponding function for Mars is compressed vertically by a factor of about 2/3. Estimate to the nearest tenth how fast a rover will hit Mars' surface after a bounce of 15 ft in height.
A) 20.7 ft/s
B) 25.3 ft/s
C) 7.3 ft/s
D) 46.5 ft/s

Answer 1

The acceleration due to gravity on earth is g = 32.174 ft/s².
Therefore on Mars, 
g = (2/3)*32.174 = 21.45 ft/s²

When an object falls from rest over a distance h, the final velocity, v, obeys the equation
v² = 2gh
or
v = √(2gh)

Therefore, given h = 15 ft, the impact velocity on Mars is
v = √(2*21.45*15) = 25.367 ft/s
The closest given answer is 25.3 ft/s

Answer:  B) 25.3 ft/s