A box of mass m is initially at rest at the top of a ramp that is at an angle θ with the horizontal. The
block is at a height h and length L from the bottom
of the ramp. The block is released and slides
down the ramp. The coefficient of kinetic friction
between the block and the ramp is μ. What is the
kinetic energy of the box at the bottom of the
ramp?
a) mgh
b) μmgLcosθ
c) mgh - μmgLcosθ
d) mgL - μmghcosθ

In the image, the arrow is pointing to a celestial object. which attribute disqualifies the object from being a planet?

Select the word from the list that best fits the definition classification of most stars on the h-r diagram

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