Question

A train is moving with a velocity of 90 kmph. when the brakes are applied , the retardation produced is 0.5 mpssquare . find a) the velocity after 10 s b) the time taken by the train to come to rest.

Answer 1

a) u=25m/s        {90km/h * 5/18}
    a=-0.5m/s2
    t=10s
    v=?
By first equation of motion,
v=u+at
v=25+-0.5*10
v=25-5
v=20m/s

b) u=25m/s
    a=-0.5m/s2
    v=0m/s
    t=?
By first equation of motion,
v=u+at
0=25+-0.5*t
0-25=0.5t
-25/-0.5=t
50s=t