A race car reaches the finish line and the driver slows down to come to a stop. If it takes the car 10 seconds to stop at a constant acceleration of -12mph/s. What was the car's speed at the finish line?

53.64 m/s

Explanation:

Applying,

a = (v-u)/t Equation 1

Where a = acceleration of the car, v = final velocity of the car, u = initial velocity of the car, t = time.

make u the subject of the equation

u = v-at Equation 2

From the question,

Given: a = -12 mph/s = -5.364 m/s², t = 10 seconds, v = 0 m/s (comes to stop)

Substitute these values into equation 2

u = 0-(-5.364×10)

u = 0+53.64

u = 53.64 m/s

at positions a, g kinetic energy is maximum.

at position d, potential energy is maximum.