Question

Please answer me the above question.

Answer 1

As per the question , the man is 9 m behind the train. The train starts with an acceleration of 2 m/s². The man also starts running and boards the train after 3 sec.

To find:

Acceleration of the man

Concept:

The basic idea that has to be applied is that both the train and the man shall cover equal distance in that 3 seconds such that the man can board the train.

Calculation:

Let acceleration of man be "a".

So distance travelled by train = Distance travelled by man

$= >9 + \{ \dfrac{1}{2} \times 2 \times {3}^{2} \} = \{\frac{1}{2} \times a \times {(3)}^{2} \}$

$= > 18 = \{\dfrac{1}{2} \times a \times {(3)}^{2} \}$

$= > 9a = 36$

$= > a = 4 \: m {s}^{ - 2}$

So man was having acceleration of 4 m/s².