Circular Motion
Gravitational force exists between any ... masses, regardless of size
2
Sum of t= 0, no rotation
Balanced torque
The point at which the mass of an object is concentrated
Center of Mass
The point from which an object can be suspended without moving in most cases the center of mass and center of gravity are equivalent
Center of gravity
What can be found by squaring the tangential speed and dividing by the radius.
Centripetal Acceleration
A force that acts on an object moving in a circular path. It is directed toward the center around which the object is moving.
Centripetal Force
Motion of an object affected only by gravity
Free fall
So why don't we feel how fast the Earth is moving?
The radius is so large that its acceleration is tiny
Units are Newton
Torque
a quality that measures the ability of a force to rotate an object around some axis. Parallel force to the direction of the movement
Torque
An acceleration of this nature is called a
centripetal acceleration
The acceleration of an object moving in a circular path and at constant speed is due to a
change in direction
The velocity vector of an object constantly
changes direction
An object that revolves around a single axis undergoes
circular motion
The speed of the object (defined as the magnitude of the velocity) is a
constant
Centripetal Acceleration is due only to a change in...
direction
Tangential speed depends on the ... from the object to the center of the circular path.
distance
The ratio of the squares of the periods of any two planets is .... to the ratio of the cubes of their average distances from the sun.
equal
The gravitational forces that two masses exert on each other are always
equal in magnitude and opposite in direction
Kepler's second law: An imaginary line drawn from the sun to any planet sweeps out equal areas in ...
equal time intervals
Thus, the planet travels ... when it is closer to the sun and ... when it is farther away.
faster, slower
Kepler's first law: Each planet travels in an elliptical orbit around the sun, and the sun is at one of the...
focal points
What types of force or combination of forces can provide centripetal force?
force of friction, gravity, and normal
orbiting objects are in
free fall
The centripetal force that holds the planets in orbit is...
gravitational force
Our bodies feel only a change in motion, so we don't feel the change in ... "as the world turns."
inertia
What affects Centripetal motion to move in a straight line?
inertia
Kepler's third law is called the...
law of harmonies
The ... of the planet/satellite that is in orbit does not affect the central object's speed or period.
mass
Gravitational force depends on the ... between them
masses and distance
Kepler's third law leads to an equation for the ... of an object in a circular orbit and the ... of an object in a circular orbit
period, speed
The applied force may act at an angle; however, the direction of the lever arm is always ... to the direction of the applied force.
perpendicular
Kepler's third Law: The square of a planet's orbital period is ... to the cube of the average distance between the planet and the sun.
proportional
Tangential speed (vt) is the speed of the object moving along an imaginary line
tangent to the circular path
The perpendicular distance from the axis of rotation to a line drawn along the direction of the force
Lever arm
Occurs when the clockwise torques exactly balance the counterclockwise torques. The object can then balance on a pivot point (fulcrum) without moving
Rotational Equilibrium
The average radius (r) is the distance between the ...
centers of the two bodies
What can be produced by a change in the magnitude of the velocity, a change in the direction of the velocity, or both.
acceleration
The line about which the rotation occurs is called the
axis of rotation
the centripetal acceleration is always directed toward the ... of the path
center
Centripetal force is simply the name given to the net force on an object in
uniform circular motion
When an object travels at a constant speed (equal distances in equal time intervals) along the circumference of a circle, the motion is called
uniform circular motion
When the tangential speed is constant, the motion is described as
uniform circular motion
Torque is a ..... quantity - has positive and negative directions: righty negative lefty positive
vector