physics
posted by cindy .
What average force is required to stop an 1300 kg car in 9.0 s if the car is traveling at 90 km/h?

Vf=Vi+a*t where a= Force/mass
change km/hr to m/s 
What average force is required to stop an 1300 kg car in 9.0 s if the car is traveling at 65 km/h?