Q1. Four identical masses of mass 710 kg each are placed at the corners of a square whose side lengths are 15.0 cm. What is the magnitude of net gravitational force on one of the masses, due to the other three?

Q2. A barbell consists of two small balls, each with mass 500 grams (0.50 kg), at the ends of very low mass rod of length d = 45 cm (0.45 m). The center of the barbell is mounted on the end of low mass rigid rod of length b = 0.675 m and this rod rotates clockwise with angular speed 120 rad/s. In adding, the barbell rotates clockwise about its own center, with the angular speed 120 rad/s.