1. A 5-kg disk moves in a circle at a constant speed of 4 m/s. The circle’s diameter is 3 m. What is the magnitude of the force required to make the disk move in this circular trajectory?
a. I got 26.67 once and 20N the second time and both are wrong.
2. A truck with a mass of 1350 kg is driven around a banked curve with a constant speed of 23 m/s (about 51 MPH). The curve’s radius of curvature is 55 m. What is the magnitude of the horizontal component of the normal force that would be required to produce this centripetal acceleration, in the absence of any friction?
3. In this question, “weight” means the gravitational force due to Earth. A woman has a weight of 560 N (about 127 lb) when she stands on the surface of the Earth. What would her weight if she tripled her distance from the center of the Earth by flying in a spacecraft?
4. An artificial satellite is in a circular orbit around Earth while experiencing a gravitational force of 30 N. What would the force be if the diameter of the orbit is doubled ?
5. NOTE units: 1 kN = 1000 N. In the morning, a 1,000 kg car is driven on a straight flat road, where it experiences a downward gravitational force of 10 kN which is balanced by an equal upward normal force, so that the net force acting on the car in the vertical direction is zero, and the car’s acceleration in the vertical direction is likewise zero. In the afternoon, the same car is driven at a steady speed of 12 m/s over a circular hilltop of radius 64 m, on a straight road. At the top of the hill the car experiences a downward acceleration, and the upward normal force has a magnitude