The driver of a car slams on the brakes when he sees a tree blocking the road. The car slows uniformly with an acceleration of - 5.6m/s for 4.20s marking straight skid marks 62.4m long ending at the tree.With what speed does the car strike the tree?

Answer 1

Vo*t + 0.5a*t^2 = 62.4 m.

Vo*4.2 - 0.5*5.6*4.2^2 = 62.4,
4.2Vo - 49.39 = 62.4,
4.2Vo = 111.79, Vo = 26.6 m/s.

V^2 = Vo^2 + 2a*d. Vo = 26.6 m/s, a = -5.6 m/s^2, d = 62.4 m,
V = ?.

Answer 2

^^ he's right thx bud