How many nutrons are in an atom of copper

An apple is falling from a tree. disregarding air resistance, which diagram shows the free-body diagram of the force or forces acting on the apple?

The long handle on a rake is a(n) a. lever b. screw c. wedge d. inclined plane

Electromagnetic induction. a coil of wire contains n turns and has an electrical resistance r. the radius of each turn is a. initially, inside the coil there exists a uniform magnetic field of magnitude b0 parallel to the axis of the coil. the magnetic field is then reduced slowly. the current induced in the coil is i. how long does it take for the magnitude of the uniform field to drop to zero?