Question

a train moving with a velocity of 90 km per hour is brought yo stop by applying brakes which produce a retardation of 0.5m/sec square. find the time taken by train to come to rest. Reply fast with full solution..its urgent..

Answer 1

u=90km/h = 90×5/18 = 25m/sec
v= 0m/s
a = -0.5m/s²
then using first equation of motion ,
v=u+at
0 = 25+(-0.5)t
0=25-0.5t
0.5t=25
t= 25/0.5 = 50 seconds
hope this helps

Answer 2

The time taken by train to come to rest is 50 seconds.

Given:

u = 90 km/h

Convert the initial velocity from km/h to m/s,

Therefore, $u=90 \times \frac{5}{18}=25 \ \mathrm{m} / \mathrm{sec}$

$v = 0 \ m/s$

$a = -0.5 \ m/s^2$(It is indicated in negative sign because it is retardation)

Solution:

Then, using the first equation of motion,

$v = u + at$

$0 = 25 + (-0.5)t$

$0 = 25-0.5t$

$0.5 t = 25$

$t = \frac{25}{0.5} = 50 \ seconds$