Which of the following has the most kinetic energy?
a. a bus stopped at a red light
b. a small child moving slowly on a tricycle
c. a player hanging on the rim after dunking a basketball
d. a helicopter getting ready to take off from the top of a tall building

Exercise 2. find the wavelength of a photon emitted when an electron jumps from the n = 3 energy level down to the n = 2 energy level. where is this photon in the electromagnetic spectrum?

The man of mass m1 and the woman of mass m2 are standing on opposite ends of the platform of mass m0 which moves with negligible friction and is initially at rest with s = 0. the man and woman begin to approach each other. derive an expression for the displacement s of the platform when the two meet in terms of the displacement x1 of the man relative to the platform.

The radius of an atom is closest in size to a