Use the impulse-momentum theorem to find how long the sled takes to travel from A to B.?

Question

A sled slides along a horizontal surface on which the coefficient of kinetic friction is 0.25. Its velocity at point A is 8m/s and at point B is 5m/s.

in seconds

Answer 1

F(t-t0) = m(v - v0)
F = 0.25W = 0.25mg
0.25*9.80662*t = 8 m/s - 5 m/s
t = 3/(0.25*9.80662) s
t = 1.2237 s