When brakes are applied to a bus, retardation produced is 25 cm s-2 and the bus takes 20 s to stop. Calculate (i) The initial velocity of the bus (ii) The distance travelled by the bus during this time. Final velocity v = 0 Acceleration = -25 cm/s2 or -0.25 m/s2 Time taken t = 20 s (i) Let 'u' be the initial velocity. Using the first equation of motion, v = u + at We get, u = v - at u = 0 - (-0.25)(20) = 5 m/s-1 (ii) Let 's' be the distance travelled. Using the third equation of motion, v2 - u2 = 2as We get, (0) 2 - (5)2 = 2 (-0.25) (s) s = (25/0.5) = 50 m. Concept: Distance and Displacement Is there an error in this question or solution? |