Astone with a mass of 10 kg is sitting on the ground, not moving. a) what is the weight of the stone? b) what is the normal force acting on the stone?

A) weight=mass X gravitational force

10Kg X 10 M/S 2

100 KgM/S2

100Newton

B) Force =Mass X gravitational force

10Kg X 10 M/S2

100 Newton

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