1. a car with a mass of 1,500 kilograms is moving around a circular curve at a uniform velocity of 16 m/s. the curve has a radius of 100 meters. what's the centripetal force on the car? 2. a car with a mass of 1,200 kg is moving around a circular curve at a uniform velocity of 20 m/s. the centripetal force on the car is 6,000 n. what's the radius of the curve? write your answers using 1–2 paragraphs. 3. describe the universal gravitational law. 4. evaluate the techniques and models used by ptolemy and copernicus to explain the setup of the universe.