# HPhys7

 Circular motion: motion with constant radius of curvature caused by acceleration being  to velocity.A body moving in uniform circular motion has a constant speed and is accelerated toward the center of the circle. Tangential speed is the speed of an object in circular motion. (the v in the following formula) Centripetal acceleration: acceleration toward center of circular motion;  ac = v2/r Period: time needed to repeat one complete cycle of motion (T). Centripetal force: force that causes centripetal acceleration is also toward the center.is necessary for circular motion. Newton’s Law of Universal Gravitation: Gravitational force is the mutual force of attraction between particles of matter.Orbiting objects are in free fall. F between 2 bodies depends on 1. product of their masses2. divided by the square of the distance between them F α  Newton’s law of gravitation accounts for? ocean tides.Gravity is a field force.Gravitation field strength equals free-fall acceleration.Weight changes with location. Kepler’s laws of planetary motion: 1. planets move in elliptical orbits 2. planets sweep out equal areas in equal timesBoth the period and speed of an object that is in a circular orbit around another object depend on two quantities: the mass of the central object and the distance between the centers of the objects. Torque and Simple Machines If you want to make an object move, apply a force.If you want to make an object rotate, apply a torque. Torque is a quantity that measures the ability of a force to rotate an object around some axis.Torque = product of force and the lever arm. Γ = Fdsinθ Lever arm: distance from axis of rotation to a line along which the force acts. A machine eases the load either by changing the magnitude or the direction of the force exerted to do work but does not change the amount of work done.  A machine provides a mechanical advantage. 6 simple machines: lever, pulley, wheel & axle (gears = wheel & axle), inclined plane, screw, wedge. Compound machine is two or more simple machines linked so that Fr of one machine becomes the Fe of the second; AMA of a compound machine is the product of the AMA’s of the simple machines it is made up of. Authordoctorwhogirl998 ID189624 Card SetHPhys7 DescriptionPhysics: Circular Motion and Gravitation Updated2012-12-15T18:03:28Z Show Answers