A stationary block has a charge of +6.0×10−8 C. A 0.80-kg cart with a charge of +4.0×10−8 C is initially at rest and separated from the block by 0.4 m. The cart is released and moves along a frictionless surface to a distance of 1.0 m from the block. Consider the objects as point charges.
A) Determine the electric potential energy of the initial state.
B) Determine the electric potential energy of the final state.
C) Determine the change in electric potential energy.
D) Determine the final speed of the cart. Assume that the change in electric potential energy is fully transformed into kinetic energy of the cart.

Glass is transparent to visibile light under normal conditions; however, at extremely high intensities, glass will absorb most of the light incident upon it. this works through a process known as multiphoton absorption. in this process, several photons are absorbed at the same time. if very intense light whose photons carry 2ev of energy is shined onto a material with a band gap of 4ev, that light can be absorbed through two-photon absorption, because two photons have the right amount of energy to bridge the band gap. what is the minimum number of photons of 800-nm light that are needed to equal or exceed the band gap of fused silica glass

What is special about a dc circuit ?

The bar of prob. 5/82 is repeated here. the ends of the 0.4-m bar remain in contact with their re- spective support surfaces. end b has a velocity of 0.5 m/s and an acceleration of 0.3 m/s2 in the di- rections shown. determine the angular accelera- tion of the bar and the acceleration of end a.