The combined mass of a cyclist/bike is 80 kg, the drag coefficient is 0.80, the frontal area is 0.45 m^2, and the density of air is 1.2 kg/m3. The slope of the hill is known What is the cyclist acceleration when initiating motion (zero velocity) on the steep hill with no wind?

answer; ///(74) degrees is 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

pythagoras' theorem

square root (-5^2+9^2)

square root (25+81)

square root (106)

angle is tan^-1(9/5)

neg x, pos y