Which statement regarding simple machines is correct?

they decrease the amount of work done.

they can change the size and direction of the force used to do the work

Work can be made easier or be done faster

both B & C are correct

An incident ray through the focal point of a spherical mirror will: reflect through the center of curvature. reflect back through the focal point. reflect parallel to the principle axis. reflect the same direction as the incident ray.

Amoving electron has kinetic energy k1. after a net amount of work w has been done on it, the electron is moving one-quarter as fast in the opposite direction. (a) find w in terms of k1. (b) does your answer depend on the final direction of the electron's motion?

Ascientist wants to test ways to reduce pollution in lake . what is the bestway of doing this