Question

A train is travelling at a speed of 90km/h. Brakes are applied so as to produce a uniform acceleration of=0.5ms-2. Find how for the train will go before it is brought to rest

Answer 1

Answer:

Given that,

Acceleration a=−0.5m/s  

2

 

Speed v=90km/h=25m/s

Using equation of motion,  

v=u+at

Where,  

v = final velocity

u = initial velocity

a = acceleration

t = time

Put the value into the equation

Finally train will be rest so, final velocity,v=0

0=25−0.5t

25=0.5t

t=  25/0.5

​  

 

t=50 sec

Again, using equation of motion,  

S=ut+  1/2at^2

 

Where, s = distance

v = final velocity

u = initial velocity

a = acceleration

t = time

Put the value into the equation

Where S is distance travelled before stop

s=25×50−  1/2 ×0.5×(50)^2  

 

s=625 m

So, the train will go before it is brought to rest is 625 m.