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.
is the speed of an object in circular motion. (the v in the following formula)
acceleration toward center of circular motion; ac = v2/r
time needed to repeat one complete cycle of motion (T).
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 masses
2. divided by the square of the distance between them
Newton’s law of gravitation accounts for?
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 times
Both 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.
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
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.
Physics: Circular Motion and Gravitation