A merry-go-round consists of a uniform solid disc of 225kg and a radius of 6.0m. A single 80kg person stands on the edge when it is coasting at 0.20 revolutions per sec. How fast would the device be rotating after the person has walked 3.5m toward the center. (The moments of inertia of compound objects add.)

Along wire carrying a 4.2 a current perpendicular to the xy-plane intersects the x-axis at x=−1.7cm. a second, parallel wire carrying a 3.0 a current intersects the x-axis at x=+1.7cm. part a at what point on the x-axis is the magnetic field zero if the two currents are in the same direction? express your answer to two significant figures and include the appropriate units.

An atom that has gained or lost electrons is called an _

If the specific heat of a metal is 0.850 j/g °c, what is its atomic weight?