1. A cart of mass 4 kg moves at a speed of 10 m/s to the right when it encounters a horizontal spring of spring constant 250 N/m. The maximum potential energy stored the spring in bringing the cart to rest is (A) 80 J (B) 200 J (C) 280 J (D) 400 J
2. For the same car and spring as the previous problem, what is the maximum compression distance of the spring?
(A) 1.26 m (B) 1.6 m (C) 2.5 m (D) 8 m

Unpolarized light of intensity so passes through two sheets of polarizing material whose transmission axes make an angle of 60∘ with each other as shown in the figure. what is the intensity of the transmitted beam, st?

Debbie places two shopping carts in a cart corral she pushes the first cart which then pushes a second cart what force is being exerted

Some material consisting of a collection of microscopic objects is kept at a high temperature. a photon detector capable of detecting photon energies from infrared through ultraviolet observes photons emitted with energies of 0.3 ev, 0.5 ev, 0.8 ev, 2.0ev, 2.5ev, and 2.8ev. these are the only photon energies observed. (a) draw and label a possible energy-level diagram for one of the microscopic objects, which has four bound states. on the diagram, indicate the transitions corresponding to the emitted photons. explain briefly. (b) would a spring–mass model be a good model for these microscopic objects? why or why not? (c) the material is now cooled down to a very low temperature, and the photon detector stops detecting photon emissions. next, a beam of light with a continuous range of energies from infrared through ultraviolet shines on the material, and the photon detector observes the beam of light after it passes through the material. what photon energies in this beam of light are observed to be significantly reduced in intensity (“dark absorption lines”)? explain briefly.