How much far is the Moon from Earth if it takes light 8.53 hours to travel there?

What produces light and all other electromagnetic waves? a) the photoelectric phenomena b) heated metals c) charged particles d) radioactive samples (pls explain if you can : )

Aperson stands on a platform, initially at rest, that can rotate freely without friction. the moment of inertia of the person plus the platform is ip. the person holds a spinning bicycle wheel with its axis horizontal. the wheel has moment of inertia iw and angular velocity ωw. take the ωw direction counterclockwise when viewed from above. part a what will be the angular velocity ωp of the platform if the person moves the axis of the wheel so that it points vertically upward?

Who was the first scientist to measure speed as distance over time?