I. Use the information in Figure 2 to find the force provided by the waiter at P ii. Find the upward force the hand exerts at T
ii. The drink is moved along the tray closer to the hand. Is the force needed at P to keep the tray horizontal now less, greater or the same? Explain your answer

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

it is b. absorbs thermal energy