Finding speed? what formula should be used?

Question

The driver of a car slams on the brakes when he sees a tree blocking the road. The car slows uniformly with acceleration -5.80 m/s2 for 4.30 s, making straight skid marks 63.5 m long ending at the tree. With what speed does the car then strike the tree?

Answer 1

1st apply the formula

s=ut+1/2 * a * t^2

u will get the value of u as u know

s=63.5 t=4.3 and a =-5.8

after getting the value of u, apply the formula

v^2-u^2=2as

u will get the value of v i.e final velocity.