Your friend, a 75 kg mountain climber is suspended from a cliff by a rope. Calculate the tension in the rope, in Newtons, when you lift your friend to safety. If the rope can withstand 1.25 kN of stress per square centimeter of cross-sectional area, what minimum diameter of rope (cm) is needed so that your friend does not fall into the abyss? What factor of safety would you want to apply to this diameter to be very, very sure that this rope will not break (1.5x 2x, 3x, 10x, 100x, 1000x)?