How much work is done when i apply 200 n of force to a brick wall

Which simple machine is not part of this compound machine? a. lever b. pulley c. inclined plane d. wheel and axle

The smallest particle of an element that retains its identity in a chemical reaction. true or false

Acircular ring of charge with radius b has total charge q uniformly distributed around it. what is the magnitude of the electric field at the center of the ring? 0 keq/b2 keq2/b2 keq2/b none of these answers