Along time ago, in a galaxy far, far away, electric charge had not yet been invented, and atoms were held together by gravitational forces. compute the bohr radius (a0) and the n = 5 to n = 4 transition energy (e5 − e4) in a gravitationally bound hydrogen atom.

Abaseball has a mass of 0.145 kg and approaches a bat at 40.0 m/s. after it is hit, the ball leaves the bat at 50.0 m/s directly back. find the impulse of the bat on the ball. 7.25 kg*m/s 13.1 kg*m/s 5.80 kg*m/s 1.45 kg*m/s

Complete the sentence to describe the law of conservation of energy. the law of conservation of energy states that energy cannot be created or , but it can be

Scout feels ill one day before school. her mother puts a thermometer in her mouth and the temperature begins to climb to 100°f. what is happening between the cooler thermometer and scout's body? a) scout's body is applying a force to the particles in the thermometer. b) kinetic energy is being transferred from her mouth to the thermometer. c) potential energy is being lost by the thermometer and gained by scout's body. d) the potential energy stored in foods is converted to mechanical energy to raise the mercury in the thermometer.