Woodpeckers obtain their food by pounding their beaks on tree trunks. they can do this at 98.1 meters per second which is 10 times the acceleration due to gravity. so what is the rate of acceleration due to gravity?

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

Which changes of state do the labels represent? a: b: c:

What are the factors that affect the resistance of a wire?