Question

a train is travelling at a speed of 90km/hour , breaks are applied so as to produce an acceleration of -0. 5 m/s2.how much time will a body take to come to rest.
a) 5 sec.
B) 0.5 sec.
c) 50 sec.
d) none of these​

Answer 1

Answer:

ANSWER=C)50s

Explanation:

here u=90km/hr

=90*5/18m/s

=25m/s

After applying breakes train comes at rest

therefore

v=0m/s

acceleration (a)= -0.5m/s²

By using 1st equation of motion

v=u+at

0m/s=25m/s+(-0.5m/s²) * t

0.5m/s²*t=25m/s

t=25m/s/0.5s²/m

t=50s