. During the St. Patâs celebrations, for reasons we will not discuss, a person is driving a car of mass m and speed v the wrong way out of the Physics Department parking lot, in the positive ydirection. At the same time, a law-abiding citizen in a pickup truck of mass M is traveling at unknown speed on Pine Street which makes an angle θ with the x-axis. The car and the truck collide and stick together. The fused wreckage is skidding in the positive x-direction along the horizontal road surface for a distance D until it comes to a stop. Derive an expression for the coefficient of kinetic friction, µ, between wreckage and road, in terms of m, M , v, D , θ and constants. You may use, without proof, that the normal force magnitude is equal to the weight magnitude. (No people have been harmed in the creation of this test problem.)

An charge with mass m and charge q is emitted from the origin, (x,y)=(0,0). a large, flat screen is located at x=l. there is a target on the screen at y position y(h), where y(h) > 0. in this problem, you will examine two different ways that the charge might hit the target. ignore gravity in this problem. 1.assume that the charge is emitted with velocity v(0) in the positive x direction. between the origin and the screen, the charge travels through a constant electric field pointing in the positive y direction. what should the magnitude e of the electric field be if the charge is to hit the target on the screen? express your answer in terms of m, q, y(h), v(0), and l. 2.now assume that the charge is emitted with velocity v(0) in the positive y direction. between the origin and the screen, the charge travels through a constant electric field pointing in the positive x direction. what should the magnitude e of the electric field be if the charge is to hit the target on the screen? express your answer in terms of m, q, y(h), v(0), and l.