A truck of mass 2300 kg is travelling at a constant speed of 22 m/s along a dry, level road. The driver reacts to a hazard ahead and applies the brakes to stop the truck. The reaction time of the driver is 0.97 s. The brakes exert a constant braking force of 8700 N.
1. Calculate the magnitude of the deceleration of he truck when braking.
I tried doing it two different ways,
1st was to use F = ma and I did 8700/2300 to get 3.78
2nd was to use a = (final v - initial v)/t, to get a = -22/0.97 = 22.7
I could not find a mark scheme to this question, so I do not know which method, if any is correct.