What 3 types of forces can represent centripetal force? Do Now: What 3 types of forces can represent centripetal force? An astronaut on the moon with a weight of 132 N on the moon’s surface is brought an additional moon radii away from the surface. What is his weight? A child pulls a wagon with a Net force of 20 N at a 30o angle for 10 seconds a distance of 10m. How much power is used?

Aim: Review for Forces & Energy Test HW: Study for Test

Station Activity Attempt the following problems with your partners.

Station 1 A man is swinging a 1kg rock above his head wrapped in cloth. He swings it at a rate of 4 revolutions in 8 seconds with a radius of 0.5 m. Draw the motion and sketch the direction of centripetal force, centripetal acceleration and tangential velocity. What is the tension on the cloth?

Station 2 A 1300 kg roller coaster is pulled 150m to the top of a hill at 60o by a chain with a force of 8500N. (Assume frictionless) How much work is done to reach the top? What is the PE at the top of the incline? How tall is the ride? What is the speed of the roller coaster at the bottom? What is the total Mechanical energy of the system? What is the speed halfway down the hill?

Station 3 An elevator with a 900 W motor lifts a 600N person up some height in 10 s. What is the height? A 65kg boy skateboards down a 10m high grassy hill on his skateboard. At the bottom of the hill he is only going 7 m/s. How much energy is lost due to friction? Is ME constant? 3. A satellite orbits Earth. How does it’s Force due to gravity compare to that of Earth’s?

Summary How is energy conserved? Give me more than one way. What’s important to remember regarding work? How do we describe KE and PE What are two equations for power? Change in PE=change in KE or total energy for the system is equivalent to energy lost due to friction plus KE and PE. W = FIId, must be parallel. Energy in motion or stored energy