Hold a flat piece of paper horizontally. Lift it high in front of you, and drop it. Then crumple a piece of paper into a tight ball, hold it high in front of you, and drop it from the same height. Compare the motion of the two pieces of paper.

Atrain departs from its station at a constant acceleration of 5 m/s. what is the speed of the train at the end of 20s?

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 the coefficient of kinetic friction μk between the block and the tabletop?