Which statement about electric and magnetic fields is true

a. electric fields must leave a positive charge and end on a negative charge

b. electric fields and magnetic fields start at a positive and end at a negative.

c. magnetic fields must start at the north pole of a magnet and end at the south pole of a magnet.

d. electric fields loop from south to north

Asmall 21 kilogram canoe is floating downriver at a speed of 1 m/s. what is the canoe's kinetic energy?

What is a carrier wave and how does it affect what you hear on the radio

Two steel balls, each of mass m, are welded to a light rod of length l and negligible mass and are initially at rest on a smooth horizontal surface. a horizontal force of magnitude f is suddenly applied to the rod as shown. determine (a) the instantaneous acceleration a of the mass center g and (b) the corresponding rate at which the angular velocity of the assembly about g is changing with time.