What other properties of the medium could affect the speed of a wave? plz

Lets say that an object of a certain volume has a certin mass. what happens to its mass when you double its volume?

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.

Name three different units of energy used to measure heat and describe what type of situations each is usually used.