Respuesta :

Answer:

At 10 sec the velocty is 35 m/s

At 12 sec the velocity is 12 m/s

Acceleration is linear over these coordinates

a = (v2 - v1 ) / t = (12 - 35) m/s / 2 sec = -23 m/s / 2 s

a = -11.5 m/s^2

Check:   (0 - 45) / (13 - 9) = -11.3 m/s^2