Question

A train is travelling at a speed of 90 km/hr. Breaks are applied so as to produce a uniform acceleration of 0.5 m/s ². Find how far the train will go before it is brought to rest

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Answer 1

Answer:

A train is travelling at a speed of 90 km h

−1

. Brakes are applied so as to produce a uniform acceleration of −0.5 ms

−2

. Find how far the train will go before it is brought to rest?

A

625 m

Correct Answer

B

4050 m

Your Answer

C

8100 m

D

1250 m

MEDIUM

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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=

0.5

25

t=50 sec

Again, using equation of motion, 

S=ut+

2

1

at

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−

2

1

×0.5×(50)

2

s=625 m

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

Hence, A is correct.

Answer 2

Answer:

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