posted by Alex on .
Two cars are traveling along a straight line in the same direction, the lead car at 24.5m/s and the other car at 29.8m/s. At the moment the cars are 41.4m apart, the lead driver applies the brakes, causing her car to have an acceleration of -2.05m/s2.
A) How long does it take for the lead car to stop?
B) What is the distance it travels during this time?
C)Assuming that the chasing car brakes at the same time as the lead car, what must be the chasing car's minimum negative acceleration so as not to hit the lead car?
DHow long does it take for the chasing car to stop?
A. t = (Vf-Vo)/a,
t = (0-24.5) / -2.05 = 11.95 s.
B. d = (Vf^2-Vo^2)/2a,
d = (0-(24.5)^2) / -4.1 = 146.4 m.
C. a = (Vf^2-Vo^2)/2d,
a = (0-(29.8)^2) / 82.8 = -10.7 m/s^2.
D. t = (Vf-Vo)/a,
t = (0-29.8) / -10.7 = 2.78 s.