A car travelling at 72km/h decelerates uniformly at 2m/s^2.Calculate(a)the distance it goes before it stops , (b)the time it takes to stop and (c)the distance it travels during the first and third seconds.

3 answers

a. Vo = 72,000m/3600s. = 20 m/s.
V^2 = Vo^2 + 2a*d.
0 = 20^2 - 4*d.

b. V = Vo + a*t.
0 = 20 - 2t.

c.
c. d = Vo*t + 0.5a*t^2.
Vo = 20 m/s.
a = -2m/s^2
Jak