Question

If your car accelerates from rest at a steady rate of 4.2 m/s^2, how soon will it reach 72 km/h ( 44.7 mph or 20 m/s)?

Answer 1

The car will reach 20 m/s in 4.76 seconds

Step-by-step explanation:

The car moves following an uniformly accelerated motion, therefore we know that
`v=v_0+ a(t-t_0)`

Where
`v_0 = 0` are
`t_0 =0`

Then
`t= (v)/(a)=(20 m/s)/(4.2 m/s^(2))=4.76s`