Select the three words in the following sentence that indicate it is in the third person. He thought about writing a letter, but he knew his friends might not get it in time.

in physics zero. in muscle fatigue could be high

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

where is the