Rotational Motion Flashcards
(23 cards)
is the straight line around which rotation takes place
axis
When an object turns about an internal axis—that is, an axis
located within the body of the object—the motion is called
rotation or spin
When an object turns about an external axis, the motion is called
revolution
The angle through which the object rotates is called the
angular displacement
To describe rotational motion, the most natural way to measure the
angle is not in degrees, but in
radians
1 rad is equal to
360degrees/2pi
the formula of angular displacement is
arc length (s) / radius (r)
is the number of
rotations per unit of time.
Rotational Speed
It is common to express rotational speed
in
revolutions per minute (rpm)
When the body is rotating clockwise, the sign of the velocity is
negative
Angular velocity is obtained by dividing the
angular displacement by time
Angular velocity is measured as
rad/s
When a rigid body rotates about a fixed axis, its motion is described
by its
angular position, angular velocity, and angular acceleration
The average angular acceleration is the
change in angular velocity divided by the time interval
The unit of angular acceleration is
rad/s2
If a point is on a wheel spinning about a fixed axis that is neither
speeding up or slowing down,
only the angular acceleration is zero
If a point is on a wheel spinning about a fixed axis that is neither
speeding up or slowing down,
only the angular velocity is constant
The direction of the angular acceleration at the top of a spinning
wheel in opposite directions
is the same
For an object turning about a certain radius, the acceleration will be
greatest in a turn along an
area with the smallest radius
A point farther away from the center travels a longer path at the
same time and therefore has a
greater tangential speed
An object sitting twice as far from the center moves
twice as fast
The component of the particle’s acceleration directed toward the
rotation axis
centripetal component of acceleration arad
