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.

Which of the following is considered to be a vector?               a.  temperature    b.  velocity    c.  time    d.  mass

Aplayground merry-go-round has a radius of 4.6 m and a moment of inertia of 200 kg-m2 and turns with negligible friction about a vertical axle through its center. a child applies a 26.0 n force tangentially to the edge of the merry-go-round for 15.0 seconds. if the merry-go-round is initially at rest, how much work did the child do on the merry-go-round?

Glass has a hardness that is in the middle of the hardness scale. what is the hardness of glass?