1. Two materials that can be scratched by an iron nail are ___,___ 2. Two materials that can be scratched by glass are ,___
3. What is the substance to hat can be scratched by an iron nail but not a penny?

Aspring with a mass of 2 kg has a damping constant 14 kg/s. a force of 3.6 n is required to keep the spring stretched 0.3 m beyond its natural length. the spring is stretched 0.6 m beyond its natural length and then released. find the position of the mass at any time t. (assume that movement to the right is the positive x-direction and the spring is attached to a wall at the left end.)

True or false: the cycle of seasons on the earth is caused by the tilt of the earth on its axis toward and away from the sun.

Why should seat belts not be mandatory quick plz