Question

A bus is travelling at a speed of 90 km/h. Brakes are applied so as to produce a uniform acceleration of -0.5 m/sec².Find how far the bus will go before it is brought to rest.​

Answer 1

Given that,

Acceleration a=−0.5m/s2

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=0.525

t=50 sec

Again, using equation of motion, 

S=ut+21at2

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=25×50−21×0.5×(50)2

s=625 m

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