Two trucks parked at a loading dock exert a gravitational force, F, on each other. The cargo from each truck is unloaded so that the mass of each truck becomes one-half of its original value. Which of the following represents the present gravitational force between the trucks? *

lol

explanation:

a skateboard rolling across the street - apex

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