1. Suppose a planet has half the mass of Earth but the same radius. An astronaut stands on the surface of the planet and drops a rock from a height of 2.4 m. How much longer does it take the rock to hit the ground on that planet than it would on Earth? (a) 1.2 times longer (b) v2 times longer (c) 2 times longer (d) 4.8 times longer 2. For a given mass, m, and a given distance, d, separating you and the object, which of the following would exert a stronger gravitational force on you? (a) An object of mass 7m a distance 15d away (b) An object of mass 9m a distance 5d away (c) An object of mass 8m a distance 3d away (d) An object of mass 12m a distance of 4d away 3. A particle of dust obtains a charge of -4.8 x 10-19 C. Determine how many excess electrons the dust obtained. (a) 2 (b) 3 (c) 4 (d) 5 4. The electric field at a distance of 1.0 m from a charged sphere is 100 N/C. At what distance from the sphere will the electric field be 50 N/C? (a) 1.1m (b) 1.4m (c) 2.0m (d) 4.0m 5. A current flows in a conductor from east to west. The direction of the magnetic field at a point above the conductor is (a) toward the north (b) towards the south (c) toward the east (d) toward the west 6. A power line lies along the east-west direction and carries a current of 10 A. The force acting on a 1 m segment due to Earth's magnetic field of 10* T is: (a) 102 N (b) 10 N (c) 10-3N (d) 105 N