Light travels through a material at a speed of 1.7 x 108 m/s. What is the index of refraction for the material?

Abird flies directly overhead from where you stand at an altitude of 300.0 m and at a speed horizontal to the ground of 20.0 m/s. the bird has a mass of 2.0 kg. the radius vector to the bird makes an angle \thetaθ with respect to the ground. the radius vector to the bird and its momentum vector lie in the xyxy-plane. what is the bird’s angular momentum about the point where you are standing?

An object in mechanical equilibrium is an object

The built in flash in a compact camera is usally capable of giving correct exsposure for distance up to how many meters?