Question

If a coin is tossed by a boy in a moving train and it falls behind him, then the motion of the train is
$A.$Uniform
$B.$Accelerated
$C.$Retarded
$D.$Along a circular track

Answer 1

We have to apply the concept of different types of motion to answer this question correctly. We know that if the speed remains constant then we get uniform motion. When speed increases then the motion is termed as accelerated and when speed decreases then the motion is called retarded motion.

Complete step by step solution:
To answer this problem precisely we will analyse the above given options one by one.
We will first get the idea of uniform motion. We know that when a body travels with constant speed then the motion is termed as uniform motion. During uniform motion of the train, when the coin is tossed, the coin goes up with initial speed of the train. Hence, because of inertia of motion, the coin travels the equal distance as the train and will fall in the hands of the boy.
Accelerated motion is a type of motion in which speed of the body increases. During accelerated motion the coin will fall behind the boy as due to accelerated motion the boy would have moved forward a bit.
Retarded motion can be explained as the motion in which the speed decreases. Hence, during retarded motion the coin will fall in front of the boy as due to retarded motion the boy would have slowed down a bit with the train.
We don’t need to analyse the last option as it is only related to the motion of the body which moves on the circular track with properties of circular motion and nothing to do with this problem.
From the above discussion we get the correct answer: that the motion of the train is accelerated.

Hence, option $(B)$ is correct.

Note:
We should always ponder on basic kinematic aspects. We should analyse the types of motions given in the option and their properties to get to the correct option. We should also keep in mind that the retarded motion is also called decelerated motion in some problems or books.