Why are electromagnets used in metal scrap yards? they are temporary magnets, so they can be turned on and off. they are weak permanent magnets. they are very powerful permanent magnets. they are temporary magnets, so eventually the metal just falls off.

Find v(t), given acceleration a(t)=7j and initial velocity v(0)=k

Mutt and jeff are running along a path each pushing a cart loaded with rocks. if mutt's wagon has a mass two times greater than jeff's and they want to stay together, arriving at their destination at the same time, what must happen? a) jeff should slow down so mutt can catch up. b) mutt must use half as much force to push his cart. c) mutt must use twice as much force to push his cart. d) mutt and jeff will use the same force, but mutt will take bigger steps.

Why can blue light and yellow light combine to produce white light? question 17 options: they are both primary colors of light. they absorb each other's wavelengths. because blue, yellow, and white are primary colors. they are complementary colors of light.