Question

He looks up and sees that the light in the intersection is red and slams on his brakes so that his car slows with a constant acceleration of 5.0 m/s2. After the brakes have been applied, how far does the car go before stopping?

Answer 1

given,

constant acceleration of car when it slows = 5 m/s²

Assume the initial speed of car = 29 m/s

distance taken by car before stopping = ?

using equation of motion

v² = u² + 2 a s

v is the final speed = 0 m/s

u is the initial seed of car = 29 m/s

a = - 5 m/s²

now,

0² = 29² - 2 x 5 x s

10 s = 841

`s = (841)/(10)`

s = 84.1 m

hence, if initial velocity is equal to 29 m/s then car will stop at 84.1 m