How does the speed of a light wave and sound wave change as the density of the medium through which the waves travel increases?​

When you push downward on a book at rest on a table, you feel an upward force. does this force depend on friction? defend your answer.

If a tank filled with water contains a block and the height of the water above point a within the block is 0.8 meter, what is the pressure at point a?

In automobile steering wheel is shown what is the ideal mechanical advantage blank? if the ama is eight what is the efficiency of the steering wheel?