Which device provides electrical energy to run an electric circuit

What is the average speed of a car that travels 40 mph for 1 hour and 60 mph in another hour?

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?

This is the number of complete movements of a wave per second.