MyQuestionIcon

1

You visited us 1 times! Enjoying our articles? Unlock Full Access!

Finding Average Velocity

The motor of ...

Question

The motor of an electric train can give it an acceleration of 1 m/s^2 and brakes can give it retardation of 3m/s^2. Find the shortest time in which train can make a trio between two stations 1215 m apart.

Open in App

Solution

Let the train accelerates upto a distance of 'x'm and then decelerate and stop after (1215-x)m.
So at a point x , the velocity (v) is given by v^2 = 0 + 2x .
This velocityis retarted with a deceleration of 3m/s^2.
So 2x = 23(1215-x).
This gives x = 911m.
So v^2 = 2x 911
v = 43 m/s.
Since, v = u + at ,
we get, 43= 0 + 1t
t = 43 s
Now for the decelerating journey ,
0 = 43- 3t
t =14 s.
So the total journey time = 43 + 14 = 57 seconds.

Suggest Corrections

thumbs-up

8

Similar questions

Q. The motors of an electric train can give it an acceleration of

1 m s^{- 2}

and the brakes can give a negative acceleration of

3 m s^{- 2} .

The shortest time in which the train can make a trip between two stations

1350

Q. Engine of a vehicle can give it an acceleration of

1 m s^{- 2}

and its brakes can retard it at

3 m s^{- 1}

. The minimum time in which the vehicle can make a journey between stations

A

B

having a distance of

1200 m

Q. Consider a train which can accelerate with an acceleration of

20 c m / s^{2}

and slow down with deceleration of

100 c m / s^{2}

. Find the minimum time for the train to travel between the stations 2.7km apart.

Q. An engine of a vehicle can produce a maximum acceleration of

4 m s^{- 2}

. Its brakes can produce a maximum retardation of

6 m s^{- 2}

. The minimum time at which it can cover a distance of

3 k m

Q. A local train leaves station A; it gains speed at the rate of 1

m s^{- 2}

for first 6 s and then at the rate of 1.5

m s^{- 2}

until it has reached the speed of 12 m/s. The train maintains the same speed until it approaches station B; brakes are then applied, giving the train a constant deceleration and bringing it to a stop in 6 s. If the total running time of the train is 40 s. Find (a) the distance between stations A and B. (b) Draw acceleration-time, velocity-time, and the position-time relation of motion.

View More

Join BYJU'S Learning Program

similar_icon

Related Videos

lock

Speed and Velocity

PHYSICS

Watch in App

explore_more_icon

Explore more

Finding Average Velocity

Standard XII Physics

Join BYJU'S Learning Program

CrossIcon