Question

An object is dropped 14ft above the surface of the moon. How long will it take the object to hit the surface of the moon if d^2/dt^2=-5.2 ft/sec^2?
Or see attachment.

Answer 1

Using the kinematic equation xf = xi + vi*t + 1/2*a*t^2
since the object is dropped from 14 ft above the surface your xi = 14
and in the end the object will hit the surface of the moon your xf = 0
you know the object is dropped so the your vi = 0
d^2/dt^2 is just a fancy way of saying 2nd derivative or acceleration
solve for t
0 = 14ft + 0*t + 1/2*(-5.2ft/s^2)*t^2