Suppose the electric field in some region is found to be e = kr3 ˆr, in spherical coordinates (k is some constant). (a) find the charge density rho. (b) find the total charge contained in a sphere of radius r, centered at the origin. (do it two different ways.)

Which of these statements is true? a. quarks pair with leptons to form protons and neutrons. b. quarks pair with bosons to form photons. c. quarks pair with photons to form protons and neutrons. d. quarks pair with other quarks to form protons and neutrons. e. quarks pair with electrons to form protons.

Which of the following is an example of motion in two dimensions?

Arowboat passenger uses an oar to push the boat off the dock by exerting a force of 40n for 3.0s. what impulse acts on the boat.