Presentation on theme: "And other weird, wild stuff."— Presentation transcript:
1 And other weird, wild stuff. Fc and FgAnd other weird, wild stuff.
2 Circular Motion Uniform Circular Motion Movement of an object around a fixed radiusAlso at a fixed speed.Does an object going around in a circle accelerate?YES!It changes direction constantly!
3 B. Direction is important If the object is going in a circle, what direction does the acceleration go?RAcP.S.Ac and Vcare at 90°rVcTOWARDS THE CENTER! ALWAYS, ALWAYS, ALWAYS!
4 C. FORMULAS Vc = 2πr Vc is called centripetal velocity ac = vc2 r ac is called centripetal acceleration
5 II. Centripetal ForceAccording to Newton’s 2nd LawF= maSo, Fc = macOr, Fc = mvc2rCentripetal Force ALWAYS goes toward the center due to Newton’s 2nd Law.
6 III. Centrifugal Force A “fake” force. You are in a ride that goes in a circle. You feel like you are pushing against your seat.You are notIt is your intertia……it is not a force
7 IV. Law of Gravitation Bob Newton Came up with it. The myth was he was hit in the head with an apple.Didn’t use an apple, used the moon.The moon is falling to Earth due to gravityThe Earth is being pulled to the moon with the same gravityWhy?NEWTON’S 3rd LawNewton found out that the gravity is dependent upon the mass of the two objects and the distance between them.
8 B. FORMULA Fg = Gm1m2 r2 m1 and m2 are the masses of the two objects By the way, This equation works anywhere in the universe.Fg = Gm1m2r2m1 and m2 are the masses of the two objectsr is the distance between the centers of the two objects.G= gravitational constant = 6.67 x 10-11
9 C. ExampleWhat is the force of gravity (weight) of a 10 kg dog on Earth? (I would like you to do this 2 different ways.)You are going to need the following info:g = 9.8 m/s2Mass of Earth = 5.97 x kgRadius of earth = m