A student does 25 J of work on the handle of a pencil sharpener. If the pencil sharpener does 20 J of work on the pencil, what is the efficiency of the sharpener?

How are momentum and impulse related? impulse is a whim to do something, while momentum keeps it going impulse is another name fore instantaneous momentum the impulse acting on and object is equal to the change of momentum it causes. the impulse that acts on and object is the momentum that results.

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

Asher cycles 12 miles in 16 hours. what is his speed?