Acart is moving to the right with a constant speed of 20 m s . a box of mass 80 kg moves with the cart without slipping. the coefficient of static friction between the box and cart is 0.30, and the coefficient of kinetic friction between the box and cart is 0.15. what are the magnitude and direction of the frictional force acting on the box as it moves with 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

The softest and hardest minerals are: softest hardest

The air that we breath is made mostly of which gaseous molecule