7 A boy with a mass of 25 kg is sitting in a red wagon of mass 8.5 kg which is at rest. His friend begins pulling him forward, accelerating him with a constant force for 2.35 s to a speed of
1.8 m/s. Calculate the force with which the wagon was being pulled.

25.7 N
6.5 N
19.1 N
4.2 N

Determine el momento angular de un rueda de 3000g moviendose a 10m/s con un radio de giro de 400cm

Anybody wanna ? (picture included? )

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?