Which force is a noncontact force?

A.
magnetic force
B.
impact force
C.
normal force
D.
frictional force

Two identical small charged spheres are a certain distance apart, and each one initially experiences an electrostatic force of magnitude f due to the other. with time, charge gradually leaks off of both spheres. when each of the spheres has lost half its initial charge, the magnitude of the electrostatic force will be

When using two-wire cable to feed a 240-v appliance that does not require a neutral wire, you should a. mark both ends of the white wire green. b. use the cable as is. c. use only the black wire. d. mark both ends and any exposed area of the white wire black.

At very high pressures, gases become and will eventually a) more dense; become hotter b) more dense; change to a liquid or solid c) less dense; combust d) less dense; turn into a liquid