4. The two collars A and B are initially at rest. The accelerations of the collars A and B are: aA = 2.5 t in s 2 upward aB = 15 in s 2 downward (a) What is the time at which the velocity of block C is again zero? (b) Find the distance through which block C will have moved in that time (the total time that block C is moving).

The summit of chimborazo, in ecuador, which is at a distance of about 6,384 km from the earth’s center. the bottom of the mariana trench, in the western pacific ocean, which is nearly 6,370 km from the center of the earth. on the surface of earth on the equator line.

Unpolarized light falls on two polarizer sheets whose transmission axes are at right angles. a third polarizer is placed between the first two so that its axis makes a 52-degree angle with the axis of the first polarizer. a) what fraction of the incident light intensity is transmitted through the first polaroid? b) what fraction of the incident light intensity is transmitted through the second polaroid? c) what is the angle of polarization of the light that enters the third polaroid? d) what fraction of the incident light intensity is transmitted through the third polaroid. e) what happens if the middle polaroid is removed?

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.