Question

10. When brakes are applied to a bus, the retardation
produced is 25 cm s2 and the bus takes 20 s to
stop. Calculate : (i) the initial velocity of bus, and
(ii) the distance travelled by bus during this time.
Ans. (i) 5 m s', (ii) 50 m
​

Answer 1

a = -25cm/s² = -0.25 m/s²

t = 20s

v = 0

v = u + at

u = 25 x 20 = 500cm/s = 5m/s

s = ut + 1/2 at²

= 5x20 + 1/2 x -0.25 x 400

= 50m