Which of the following is not in our sun's future?

a) white dwarf
b)black hole
c)red giant
d)main sequence

i think it's a because i don't think the sun get go down to its size. or is that dumb?

Describe the path of a ray that approaches a mirror parallel to the principal axis.

The 5-kg cylinder is initially at rest when it is placed in contact with the wall b and the rotor at a. if the rotor always maintains a constant clockwise angular velocity v = 6 rad> s, determine the initial angular acceleration of the cylinder. the coefficient of kinetic friction at the contacting surfaces b and c is mk = 0.2.

A0.580-kg rock is tied to the end of a string and is swung in a circle with a radius of 0.500 meters. the velocity of the rock is 4.50 m/s. what is the centripetal force acting on the rock? 15.5 n 5.22 n 69.8 n 23.5 n