Which statements describes friction? check all that apply. it results from microscopic bumps and ridges. it causes a change in motion. it occurs in the same direction as the push force. it is the opposite to the direction of the motion. it is parallel to the surfaces that rub together.

Aresistor with an unknown resistance is connected in parallel to a 9 ω resistor. when both resistors are connected in parallel to an emf source of 21 v, the current through the unknown resistor is measured with an ammeter to be 4 a. what is the resistance of the unknown resistor? answer in units of ω.

A4.0-cm tall light bulb is placed a distance of 32.0 cm from a concave mirror having a focal length of 16.0 cm. determine the image distance

What ia the energy of an object because of its potential and kinetic energies