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Periodic Motion
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Gravity
Terms in this set (40)
axis
Straight line around which an object spins
rotation
Spinning motion when turning about an internal axis
revolution
Spinning motion when turning about an external axis (Going around an axis that is not inside it)
linear speed (v)
Scalar, how fast an object is moving; linear distance moved per unit time
radial distance (r)
Distance from the axis to an object rotating about that axis
tangential speed (v)
Scalar, speed of an object moving along a circular path perpendicular to the radial distance; know as linear speed
Angular speed (w)
Scalar; number of revolutions per unit time; usually reported in revolutions per minute (RPM); must be converted to radians per second (rad/sec) when used with problem solving, rotational speed
centripetal
Center seeking
centripetal force
Force perpendicular to the path of a moving object that produces circular motion
centripetal acceleration (Ac)
Acceleration toward the center of circular motion, also called radial acceleration
centrifugal
center fleeing
centrifugal force
Apparent outward force on a rotating or revolving object, not real
g-force
Not actually forces, reference to the feeling experienced under a certain amount of acceleration
angular displacement (theta)
Angle through which a rigid objects rotates about a fixed axis, positive is counterclockwise, negative is clockwise, measured in radians
average angular velocity (omega)
going in a circle speed, ratio of change in angular displacement to time interval, measured in radians per second
average angular acceleration (α)
Going in a circle acceleration; ratio of change in angular velocity to time interval; rate at which spinning motion is speeding up or slowing down; unit is rad/s^2
tangential acceleration (a sub t)
Acceleration vector that points along a straight line tangent to the circle while an object is spinning; same as linear acceleration; result of the change in speed; zero if in uniform circular motion
center of gravity
Point at the center of an object's weight distribution where gravity is considered to act; found at the geometric center (may or may not be at a location on the object); same as the center of mass for small objects
center of mass
Point at the center of an object's mass distribution where all of its mass is considered to be concentrated; found at the geometric center (may or may not be at a location on the object); same as center of gravity for small objects
topple
To fall in a circular path or rotate; occurs due to a torque
torque (τ)
Measurement of the ability of a force to rotate an object around an axis; tends to produce rotation; cause of toppling
lever arm (d)
Distance between the fulcrum/axle and the perpendicular force applied
balanced torques
When torque CCW is equal to torque CW; when the net torque or sum of all torques is zero; rotational equilibrium
moment of inertia (I)
Aka rotational ___
Reluctance of object to change state of rotation determined by mass of object and location of axis of rotation of revolution. Closer the mass distribution is to the center of mass, the less ___ the object has, making it easier to rotate
rotational work
Work done when spinning
rotational energy
Energy due to spinning or rotating; measured in Joules
angular momentum (L)
Inertia in rotational motion; product of the moment of inertia and angular speed of a rotating object; vector quantity
precession
Circular motion of the axis of a spinning object
simple harmonic motion (SHM)
Repetitive motion of an object where its acceleration is directly proportional to its displacement (a vibration or oscillation about an equilibrium position in which a restoring force is proportional to the displacement from equilibrium)
equilibrium
A state of balance
- Linear ___:
No net force -> No linear acceleration; ∑F=0
- Rotational ___:
No net torque -> No rotational acceleration; ∑ τ=0
period (T)
Time to complete one full cycle of motion
amplitude (A)
Maximum linear displacement from equilibrium position
length (ℓ)
Distance from point of rotation to center of mass; usually with respect to pendulums
compression (x)
Length measured from fixed point to center of mass; usually with respect to elastic objects (used with rubber bands, springs, etc.)
extension (x)
Length measured from fixed point to center of mass; usually with respect to elastic objects (used with rubber bands, springs, etc.)
Hooke's Law
The distance of extension or compression (x) is directly proportional to the force applied by the spring (Fs); only applies to materials not stretched beyond their limits
Equal to -kx
spring constant (k)
Ratio of force to stretch; measured in N/m; applies to any elastic object (spring, rubber band, person, hair, etc.), dependent upon shape, size, thickness, composition, etc.
Is found by rearranging Hooke's Law to equal -Fs/x
elastic potential energy
Energy by virtue of a spring being stretched or compressed
simple pendulum
An object (bob) suspended from a string of length ℓ where the angle of swing ϴ is 15° or less
periodic motion
Motion that repeats itself at regular intervals
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