Question

A car going 72.0 km/h (20.0 m/s) slows down to 36.0 km/h (10.0 m/s) in 5.00 seconds. Calculate the acceleration in

m/s?

m/s2

-2.00

-7.00

-30.0

-60.0

Answer 1

-2 m/s^2

Explanation:

Just as you would calculate the velocity when a body moves from point A to point B in a time T, we are going to calculate the acceleration as the difference of the velocities (final - initial) and divide it by the time it took:

Velocity_final = 10 m/s

Velocity_initial = 20 m/s

Time = 5 s

acceleration = (Velocity_final - Velocity_inital)/Time

= (10 m/s - 20 m/s)/5 s

= (-10 m/s) / 5s

= -2 m/s^2

The acceleration in m/s^2 is -2