Why should the lock and key be gay?

Aprojectile is launched horizontally 10m above the ground and with an initial velocity of 15 m/s. a) determine the magnitude and direction of projectile velocity at t= 1.3s b) determine the magnitude and direction of projectile acceleration at t=1.3s

Observations show that interstellar clouds can have almost any shape and

Two identical stars with mass m orbit around their center of mass. each orbit is circular and has radius r, so that the two stars are always on opposite sides of the circle. (a) find the gravitational force of one star on the other. (b) find the orbital speed of each star and the period of the orbit. (c) how much energy would be required to separate the two stars to infinity?