A car of mass 400kg moving initial at 36km/h increases to 120km/h in 6sec, what is the force acting on the car?
Mechanics - physics - drwls, Saturday, January 5, 2013 at 2:17am
Force = Mass x Acceleration
For the force to be in Newtons, the Mass must be in kg (400 kg in this case), and the acceleration must be measured in m/s^2.
In your case, acceleration is
(84 km/h *1000 m/km)*)(1h/3600 s)/6 s
= 3.889 m/s^2
F = 400 kg*3.889 m/s^2 = 1556 N