Question

By seeing a child on a railway track the driver applies brakes . the speed of train is reduced from 90 km/hr to 36 km/hr 5s then train retards by​

Answer 1

Answer:

Initial velocity u = 90 km/h =25 m/s

Final velocity v = 0 m/s (brought to rest)

Distance travelled s in coming to rest = 25 m

Using the relation,

v² - u² = 2 a s, where a is the acceleration

0² - 25² = 2 . a . 25,

a = - ( 625/50) = - 12.5 m/s². The retardation is 12.5 m/s² ( negative sign in a implies it is retardation).