A 1210 kg rollercoaster car is moving 6.33 m/s. As it approaches the station, brakes slow it down to 2.38 m/s over a distance of 4.20 m. How much force did the brakes apply?
+37084 F=ma
vf=vo + at rearranging: (vf-vo)/t = a Substitute into the next equation
xf=xo+vot+1/2at^2
4.2 = 0 + 6.33(t) + 1/2 (2.38-6.33)/t * t^2
4.2 = 6.33t + (-1.975)t
t=.964409 sec
(vf- vo)/t = a
(2.38-6.33 )/ t = a = -4.09577 m/s^2
F=ma = 1210 kg (-4.09577 m/sec^2) = - 4955.88 J (negative because it is opposite to the motion of the coaster)
