A100 kg mass is pulled along a frictionless surface by a horizontal force f such that its acceleration is 8.0 m/s2. a 20 kg mass slides along the top of the 100 kg mass and has an acceleration of 3.0 m/s2. (it thus slides backward relative to the 100 kg mass.) (a) what is the frictional force exerted by the 100 kg mass on the 20 kg mass? (b) what is the net force acting on the 100 kg mass?

The intensity, or loudness, of a sound can be measured in decibels (db), according to the equation , where i is the intensity of a given sound and is the threshold of hearing intensity. what is the intensity, in decibels, [i(db)], when ? use a calculator. round to the nearest whole number. 8 9 19 80

The nuclear potential that binds protons and neutrons in the nucleus of an atom is often approximated by a square well. imagine a proton conned in an innite square well of length 105 nm, a typical nuclear diameter. calculate the wavelength and energy associated with the photon that is emitted when the proton undergoes a transition from the rst excited state (n 2) to the ground state (n 1). in what region of the electromagnetic spectrum does this wavelength belong?

Ihave this 50 question test the layer of earth's atmosphere where atoms and molecules escape into space is referred to as the a) exosphere b) ionosphere. c) mesosphere d) thermosphere