A proton and an alpha particle are momentarily at rest at adistance r from each other. They then begin to move apart. Find thespeed of the proton by the time the distance between the proton andthe alpha particle doubles. Both particles are positively charged. The charge and the massof the proton are, respectively, e and m. The charge and the massof the alpha particle are, respectively, 2e =and 4m.
Find the speed of the proton Vf(p) by thetime the distance between the particles doubles.
Express your answer in terms of someor all of the quantities e, m, r, and epsilon 0.

A33.1 g copper object is launched from a 1.5 m 30° steel incline positioned on the floor by being pulled up a string attached to a 50.0 g mass suspended vertically over a pulley. the object is projected towards a glass table where it lands when it is at the point along its trajectory with the lowest speed. it comes to a halt when it clears the opposite edge of the table. it then falls and lands on 9 physics texts each 5 cm thick that are stacked on the floor on the opposite side of the table. assume that the table does not have a ledge and the rectangular object experiences 0.05 n of air resistance as it falls towards the books. how far and how long did the object travel and how fast does it hit the books. assume that at the moment the copper object leaves the incline, the massless string and ideal pulley break off

Two polarizers are oriented at 40∘ to each other and plane-polarized light is incident on them. if only 16 percent of the light gets through both of them, what was the initial polarization direction of the incident light?

The speed of light can be used to measure the