Question

Why do we get hurt when we come in front of a moving bicycle?

Answer 1

Moving bicycle moves with a force and speed. So when you go in front of a bicycle you will get crushed with the bicycle moving with heavy force thus you will get hurt.

Complete step by step answer:
A moving bicycle moves with a force and a speed which is greater than the walking speed of a human.Impulsive force (F) is equal to $F = \dfrac{I}{{\Delta t}}$ , where I is the impulse and $\Delta t$ is the change in time.As the time of impact between us and the bicycle is very less, therefore, the impulsive force will be very large and we get hurt when we come in front of the moving bicycle. We get hurt because of the impulsive force executed by the bicycle.
Additional Information: Speed is a scalar quantity that refers to "how fast an object is moving." Speed can be said as the rate at which an object covers distance. Speed is the ratio of distance and time whereas velocity is the ratio of displacement and time. Speed and velocity are not the same.

Note: Forces that act for a very short time are called impulse forces. The product of the impulsive force and the time is called the impulse. The impulse is equal to the change of momentum (M) caused by the impulsive force (F).