4. When a voltage of 30 V is applied across a resistor it generates 600 W of power; what is
the resistance of this resistor?

The sun’s mass is 2.0×10^ 30 kg, its radius is 7.0×10 5 km, and it has a rotational period of approximately 28 days. if the sun should collapse into a white dwarf of radius 3.5×10 3 km, what would its period be if no mass were ejected and a sphere of uniform density can model the sun both before and after?

Your physics assignment is to figure out a way to use electricity to launch a small 6.0-cm-long plastic drink stirrer. you decide that you'll charge the little plastic rod by rubbing it with fur, then hold it near a long, charged wire, as shown in figure p23.56 . when you let go, the electric force of the wire on the plastic rod will shoot it away. suppose you can uniformly charge the plastic stirrer to 10 nc and that the linear charge density of the long wire is 1.0 x10-7 c/m. what is the net electric force on the plastic stirrer if the end closest to the wire is 2.0 cm away?

Identify the arrows that represent the process of cooling..