Question

An aeroplane makes in emergency landing without landing gear. If the aeroplane touches down with a horizontal speed of 60.0ms^-1 and the coefficient of friction for aluminium on asphalt is μ = 0.500, how far will the aeroplane slide before coming to rest? You may assume that acceleration due to gravity is 10.0ms^-2 and that air resistance is negligible.

Answer 1

Fp = Mg*sin 0 = 0.
Fn = Mg*Cos 0 = Mg = Normal force.
Fk = u*Fn = 0.50*Mg.

Fp-Fk = M*a.
0-0.5Mg = M*a, Divide by Mg:
-0.5 = a/g = a/-10, a = 5 m/s^2.

V^2 = 60^2 - 10d.
0 = 3600 -10d, d = 360 m.

Answer 2

Fp = Force parallel to the surface.