Actinium-226 has a half-life of 29 hours. If 100mg of actinium-226 disintegrates over a period of 58 hours, how many mg of actinium-226 will remain?

If jerome is swinging on a rope and transferring energy from gravitational potential energy to kinetic energy, is being done.

What happens when a rubber rod is rubbed with a piece of fur?

A14 kg rock starting from rest free falls through a distance of 5.0 m with no air resistance. find the momentum change of the rock caused by its fall and the resulting change in the magnitude of earths velocity. earth mass is 6.0 * 10^24 kg. show your work assuming the rock earth system is closed.