A librarian moonlighting as a magician wants to pull one book out of a stack of books. The stack is seven books high and all the books are of roughly equal mass M, of comparable size, and the coeffi- cients of friction between the books are u, and jux- The librarian needs the third book in the stack, counting from the bottom. The librarian gives the third book a hard, straight yank with a force of magnitude F perpendicular to the stack. In terms of M, g, and the appropriate coefficient of friction. what is the horizontal force, F, with which she must yank the book?

Like a key in a lock, the shape of the. must bind with the. of the recieving neuron

Which statements about tornadoes are true? check all that apply. (a) about 12,000 tornadoes hit the united states every year. (b) a tornado looks like a funnel. (c) tornadoes are deadly atmospheric storms that cause millions in damages each year. (d) tornadoes can reach wind speeds of more than 300 miles per hour. (e) kansas is the state with the most tornadoes. (f) you will always notice a funnel before a tornado strikes.

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?