a block of wood has dimensions 30centimeter, 20 centimeter, 15 centimeter and a mass of 1.80 kg. find its density in SI

Ametal ball with a mass of 0.028 kg is dropped from rest at a height of 1.0 meters above the ground. assuming the energy in the ball is conserved, how much kinetic energy will the ball have when it is 0.5 meters above the ground?

Alfred pushes on a heavy box, but cannot move it. the box has a lot of inertia motion friction gravity

The energy equivalent of the rest mass of an electron is