Q1: what is the mass of a planet, in units of Earth's mass Me ( mass of the earth ), whose radius is twice the radius of Earth and whose escape speed is twice that of the Earth


Q2: A spherical shell has inner radius R1, outer radius R2 . and mass M. distributed uniformly throughout the shell. The magnitude of the gravitational force exerted on the shell by a point particle of mass . located a distance d from the center ( d<R1 ) is


Q3: A planet is in a circular orbit around the Sun. Its distance from the sun is four times the average distance of Earth fom the Sun. The period of this planet. in Earth years, is


Q4: each of the four corners of a square with side a is occupied by a point mass m. There is a fifth mass. also m, at the center of the square. To remove the mass from the center to a point very far away the work that must be done by an external agent is given by