The star betelgeuse has a temperature of 3400 k and a luminosity of 13,200 lsun. calculate the radius of betelgeuse relative to the sun.

Aray of light traveling parallel to the principal axis of a concave mirror will be reflected through the mirror's

Place me with this question is my last question

Diego is trying to lift a piano to the second floor of his house. diego uses a pulley system and gives a big lift to the piano. the piano moves upward, then stops, and then it starts to fall to the ground. which list best describes the forces on the piano in the proper order? a.positive force, balanced force, negative force b.negative force, balanced force, positive force c.positive force, unbalanced force, negative force d. negative force, unbalanced force, positive force