When a carpet is beaten with a stick dust comes out of it

This can be explain through Newton’s first law of motion where an object at rest remain in rest unless acted upon by an unbalanced force. Hence, the dust particles having inertia and trapped within the pores of the carpet has the tendency to remain at the state of rest, it does not move and resist motion but when the carpet is beaten with a stick, dust comes out because the force from a stick acted upon it.

it is a negative acceleration

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me