What decibel level can cause hearing damage to begin

Avery hard rubber ball (m = 0.5 kg) is falling vertically at 4 m/s just before it bounces on the floor. the ball rebounds back at essentially the same speed. if the collision with the floor lasts 0.05 s, what is the average force exerted by the floor on the ball?

Infrared rays have a shorter wavelength than question 11 options: x-rays. ultraviolet rays. radio waves. gamma rays.

When electrons are added to the outermost shell of a carbon atom, it forms--an anion that has a larger anion that has a smaller cation that has a larger cation that has a smaller radius.