One car has twice the mass of a second car but only half as much kinetic energy. When both cars increase their speed by 8.0m/s they then have the same kinetic energy. What were the original speeds of the two cars?

Will you chech and finish these for me, because i am stumped with them.

The necleus of an atom is made up of what subatomic particles?

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?