d = Vo*t + 0.5at^2 = 60m/s.
25*3 + 0.5a(3)^2 = 60,
75 + 4.5a = 60,
4.5a = -15,
a = -3.3333m/s^2.
Vf = Vo + at = 25 + (-3.3333)3 = 15m/s.
A driver of a car that is going 25 m/s suddenly notices a train blocking the road. At the instant the brakes are applied, the train is 60 m away. The car decelerates uniformily and stikes the train 3 secs later. (a) How fast was the car moving on impact? (b) What was the magnitude of its acceleration during the 3 secs?
1 answer
0 answers