Matilda has a 100 g rock sample. She knows that the rock contains uranium-238 and that the half-life of uranium-238 is 4.5 × 109 years. If she cuts the rock sample in half, what happens to the half-life of the uranium?
A. The half-life increases.
B. The half-life decreases.
C. The half-life remains the same.

a longitudinal wave moves energy that is to the direction of the wave’s movement. - true

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

electric field is a function of 1/r^2

yes, the force per unit charge for a point charge is inverse square law.