A uniform disk can rotate around its center like a merry-go-round as shown in figure. The disk has a radius of 10 cm and a mass of 300 grams. Starting from rest, the disk rotates to an angular
velocity of 300 rad/s, counterclockwise, in 1 = 2.5 seconds, due to four forces that are applied to
the disk as indicated in figure.
a Calculate the moment of inertia of the disk
b. What is the magnitude and direction of angular acceleration of the disk?
c. Using Newton's second law for rotation determine the magnitude of unknown force F4
F1 = 2 N
F2=3N
45N
5 cm 5 cm
F=?
F3 = 4N

You are the coordinator for a program that is going to take place at night in a rectangular amphitheater in the mountains. you will have no access to any electricity, but you must be able to illuminate the entire grounds. you know the intensity of the light from a lantern varies inversely as the square of the distance from the lantern. suppose the intensity is 90 when the distance is 5 m. a. write an equation to model the situation. b. solve for the constant of variation. c. write the equation to model the situation using the constant () of variation. d. you have been given lanterns with 40 light intensity. use your equation to solve for the distance from the lantern. e. you need to illuminate 225 km. how many meters do you need to light? f. how many lanterns will you need?

Are formed where bumps from two surfaces come into contact ?

In general what determines whether atoms will form chemical bonds?