The spectral lines of two stars in a particular eclipsing binary system shift back and forth with a period of 3 months. The lines of both stars shift by equal amounts, and their Doppler shifts indicate an orbital speed of 88,000 m/s for Star 1 relative to Star 2. What are the masses of the two stars? Assume that each of the two stars traces a circular orbit around their center of mass. (Hint: See Mathematical Insight 15.4.)

An object is dropped from a tower, 400 ft above the ground. the object's height above ground t seconds after the fall is s(t)equals400 minus 16 t squared. determine the velocity and acceleration of the object the moment it reaches the ground. the velocity of the object the moment it reaches the ground is nothing ft/s.

Positrons are spontaneously emitted from the nuclei of

Aparticle's position is given by x = 3.00 - 9.00t + 3t2, in which x is in meters and t is in seconds. (a) what is its velocity at t = 1 s? (b) is it moving in the positive or negative direction of x just then? (c) what is its speed just then? (d) is the speed increasing or decreasing just then? (try answering the next two questions without further calculation.) (e) is there ever an instant when the velocity is zero? if so, give the time t; if not, answer "0". (f) is there a time after t = 3 s when the particle is moving in the negative direction of x? if so, give the time t; if not, answer "0".