18. in a solid conductor such as a metal, what is the cause of an electric current? a. a flow of positive and negative charges. b. a flow of positive charges only. c. +a flow of negative charges only. d. a flow of protons. e. a flow of neutrons.

The sun generates both mechanical and electromagnetic waves. which statement about those wave is true?

Astone is dropped with no initial velocity from the top of a cliff and hits the ground a time of 3.9 s later. what is the height of the cliff, in units of meters? you may assume that air resistance is negligible. give the answer as a positive number question 15 a figure skater is rotating at a rate of 200 revolutions per minute. what is the angular speed, in units of rad/s? 200 o 20.9 12000 o 3.33

One object has a mass of 1 kg and another object has a mass of 3 kg. if the speeds are the same, which of the following is true about their kinetic energy?