Question

What is the acceleration (in m/s^2) of a vehicle that changes its velocity from 85 km/h to a dead stop in 13 s?

Answer 1

120 km/h) / (12 s) = 10 km/h/s; write it as -10 km/h/s because the vehicle is decelerating.

Convert to m/s²:
(-10 km/h/s)(1000 m/km)(1 h/3600 s) = -2.8 m/s² (to 2 significant figures).