Person sitting in the bus experiences a sudden jerk when the bus begins to move. Why ?

Inertia of motion Inertia of rest Inertia of turning Inertia of acceleration

Inertia of rest

By first Law of Motion, Inertia of rest is the fundamental property possessed by a body to oppose any change in its state of rest. That is to say that the body does not want to change its state of rest, but wants to continue staying itself in the same state.