Q1. A 20 kg block is at rest on a horizontal floor. If you push horizontally on the 20 kg block with a force of 50 N, it just starts to move.
A) What is the normal force acting on block?
B) What is the coefficient of static friction?
C) A 20 kg block is stacked on top of the 20 kg block. Both blocks are glued together. What is the magnitude F of force, acting horizontally on the two blocks, that is required to make the two blocks start to move?
Q2. The spontaneous fission rate of 239U is 1 fission per gram per 1.00 sec. Show that this is equivalent to half-life for fission of 5.6 x 1 0^15 years.