A system of 6 forces attached to a point: P1=44N α1=30°

P2=4N α2=90°

P3=12N α3=150°

P4=20N α4=210°

P5=28N α5=270°

P6=30N α6=330°

Find: value, direction, return of the resultant force.

Adiver in midair has an angular velocity of 6.0 rad/s and a moment of inertia of 1.2 kg·m2. he then pulls is arms and legs into a tuck position and his angular velocity increases to 12 rad/s. the net external torque acting on the diver is zero. what is his moment of inertia in the tuck position?

When you push downward on a book at rest on a table, you feel an upward force. does this force depend on friction? defend your answer.

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?