Guess if you can?

Question

there's an engine system in a train with a retardation of0.5ms-2. the train travels with a speed of 54ms-1 towards the train station 'A'. from what distance will the brakes should be applied to stop the train at 'A'.???

HINT:solve using equations of motion

Answer 1

Stopping train means final velocity = 0.

v= 0 and u = 54m/s/s. You gave a = -0.5m/s/s

using v^2 - u^2 = 2as, we get

s = [v^2 - u^2 ]/2a

   = [0 - 54^2]/ 2(-0.5)

   = 54^2m

   = 2916m

am I right?

Answer 2

V=AT     54m/s = -.5T     T=54/.5  

T=108 seconds for the train to stop.

the average speed of the train during the stop is 54/2= 27m/s

S=VT = 27 x 108 = 2916 meters to stop.

Answer 3

2916 m