How is energy conserved when a pan of water on an electric stove to a boil

The of a machine determines its "usefulness." a. input force b. output force c. mechanical advantage

An initially unpolarized light if intensity 500 w/m^2 passes through four polarizers. the transmission axis between adjacent polarizers is 45∘. what percentage of the initial intensity is transmitted by the system?

Given the position vector of the particle r(t)=(t+1)i+(t^2−1)j+2t k, find the particle's velocity and acceleration vectors at t=1