Question

5. A car accelerates at a rate of 5.0 m/s2. If its original speed is 15 m/s, how many seconds will it take the car to reach a final speed of 45 m/s?

Answer 1

Answer:

6 seconds

Explanation:

Vı=Vf+at

so

t=Vf-Vi÷a

t=45-15÷5

t=6 seconds

Answer 2

Answer:

6 seconds.

Explanation:

We can easily apply here the first equation of translational kinematics i.e. v=u+at; where v=final velocity/speed( here 45m/s), u=initial velocity/speed(here 15m/s), a=Accleration of the body( here 5m/s²) and t=Time taken to reach "v" or final velocity(which is to be found). Easily substituting the values of "v, u and a" will yield 6 seconds as answer from the above mentioned equation.