I think Option (3) The arms mostly contains old blue and blue-white stars Explanation: Spiral arms are the regions in stars extending from the middle of spiral galaxies and the barred spiral. Those long, thin areas look like a spiral and therefore give their name to spiral galaxies. Spiral arms, though, include many young, blue stars, that render their arms so bright (due to the high mass density and the fast stellar forming rates).
Work is said to be done when an object moves due to a force applied. Work is calculated by multiplying the force applied and the distance traveled due to the force. It is expressed as:
