Question

A racecar beginning at rest accelerates at a rate of 4.0 m/s2. It takes the car 21s to reach the end of the track. How long is the track in kilometers?

Answer 1

2.289 km

Step-by-step explanation:

We can simply solve this by applying motion equations

where

s - distance

u - initial velocity

a-acceleration

t - time

`s = ut +(1)/(2) at^(2)\\  = 4*21 + (1)/(2)*10*21^(2)  \\= 2.289 km`