1. The acceleration due to gravity at a point 150 km above the surface of a planet is 7.81 m/s?. The radius of the planet is 2.48 x 10' m. (T - 6 marks) a) What is the mass of the planet? b) What is the speed of a satellite orbiting 150 km from the surface? c) What is the acceleration due to gravity on the surface of this planet? 2. Calculate the electric force between two protons that are 5.0 . 10-12 m apart. Do the protons attract or repel? (T - 2 marks, C - 2 marks)3. Two stationary charges, A {+3 at} and B [+5 uE] are 20 cm apart. Where should you place a third charge, C [-5 pt] so that it does not move when you let go of it? [T - 6 marks, C - 1 marks] 4. For the following diagram below {It - 10 monks] a] 1iiii'hat is the electric eld at point I? b} 1ii'ii'hat is the electric potential at point I? c] if a particle of charge -3 Hi: is moved to it, what is the net force acting on the particle? -2 IJC 20 cm 25 cm