Question

a car starts from rest and accelerates at 4 m/s2. how much time will it take the car to reach a speed of 20 m/s?

Answer 1

t=5 seconds

Step-by-step explanation:

To solve, use kinematic equation #1,
`v_f=v_i+at`, rewritten to solve for t:

`t=(v_f-v_i)/(a)`. For this problem, let

`v_f=20(m)/(s)\\v_i=0.0(m)/(s)\\a=4.0(m)/(s^2)`

So,

`t=(20.0(m)/(s)-0.0(m)/(s))/(4.0(m)/(s^2))\\t=(20.0(m)/(s))/(4.0(m)/(s^2))\\t=5s`