Kinetic Friction?

Question

An experimental rocket plane lands and skids on a dry lake bed. If it's traveling at 83.0 m/s when it touches down, how far does it slide before coming to rest? Assume the coefficient of kinetic friction between the skids and the lake bed is 0.710.

Answer 1

Let the weight of the rocket plane to be m. We have:
ma = F = - mg*0.710
a = -9.8*0.710 = -6.958(m/s^2)
S = |v^2/2a| = 83.0^2/(2*6.958) = 495(m)
When it touches down, it slides 495m before coming to rest.