A 10060-kg freight car is rolling along a track at +3.00 m/s. Calculate the time needed for a net force of -990 N to stop the car.
0 = 3 + a t
a = F/m = -9.90 *10^2 / (1.01*10^4) = - 9.8* 10^-2 m/s^2
so
9.8 *10^-2 t = 3
t = 300 / 9.8 = 30.6 s
a = F/m = -9.90 *10^2 / (1.01*10^4) = - 9.8* 10^-2 m/s^2
so
9.8 *10^-2 t = 3
t = 300 / 9.8 = 30.6 s