When two air masses with different characteristics meet what happens

Debbie places two shopping carts in a cart corral she pushes the first cart which then pushes a second cart what force is being exerted

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?

What is the single most important equation in all of physics?