Question

The distance between two stations is 240 Km. The train takes 4 hours to cover this distance. Calculate the speed of the train.

Answer 1

Hint: We have to consider what is given in the problem. The distance travelled by the train is given in kilometers and the time taken by the train to travel between two stations is given in hours. So the velocity of a body is defined as the distance travelled the body divided by the total time taken to travel that particular distance.

Complete step by step answer:
So the train takes 4 hours to travel a distance of 240 km between the two stations. So the train is supposed to travel with a constant velocity along a straight track.
The velocity of a body is given by the distance travelled by the body divided by the total time taken to travel that distance. So it can be written as,
$\text{Velocity(v)}=\dfrac{\text{Distance}}{\text{Time}}$
So the time is 4 hours and the distance is 240 km. So substituting the value of distance and time in the above equation we get,
$\text{v}=\dfrac{240km}{4hr}$
$\therefore \text{v}=60\text{ Km/hr}$
So the velocity of the train is 60 Km/hr.

Additional Information:
Velocity is the rate of change of position with respect to time.
Velocity is a vector quantity which means it has both direction and a magnitude.
Speed is the scalar form of the velocity, it only tells you how fast the object is moving, it doesn’t give information about the direction in which the body is travelling.
The velocity time graph of an object with constant velocity will be a line that is parallel to the time axis.
If the curve or line in the velocity time graph is perpendicular to the time axis, the velocity is theoretically infinite.

Note: Here the velocity in meter per second is v=16.67 m/s because 1km=1000m and 1hr=3600s.
In this problem we are considering that the train travelled 240 km with a constant velocity. If the velocity had varied while travelling, an acceleration could have been produced, so the equation we used in the problem would not hold.
Also the railway track was considered relatively straight with no turns involved, because curvature in a path leads to velocity change.