module 4

Question 1

is an imaginary point that allows for a mathematical “shortcut” in calculating
these unknowns.
also called the instantaneous center of zero velocity (IC). It
lies on an imaginary axis of zero velocity, about which the body appears to rotate at a
given instant. This axis is always perpendicular to the plane of motion.

Answer 1

instant center

Question 2

the point fixed to a body undergoing planar
movement that has zero velocity at a particular instant of time. At this instant, the velocity
vectors of the other points in the body generate a circular field around this point which is
identical to what is generated by a pure rotation.

Answer 2

The instant center of rotation, also called instantaneous velocity center, or also
instantaneous center or instant center,

Question 3

often described using a plane figure moving in a

two-dimensional plane.

Answer 3

Planar movement of a body

Question 4

is the point in the moving plane around which

all other points are rotating at a specific instant of time.

Answer 4

The instant center

Question 5

Consider a rigid body rotating in a plane. We wish to determine the velocity of a
point A on the rigid body given the known velocity of another point B on the rigid body.
The directions of the velocities are known and they are nonparallel. The figure below
illustrates the setup of the problem.

Answer 5

Case 1

Question 6

Consider a rigid body rotating in a plane. We wish to determine the angular velocity
of the rigid body given the known velocities of points A and B on the rigid body. These
velocities are parallel and pointing in the same direction. The line joining points A and B
is perpendicular to the direction of the velocities. The figure below illustrates the setup of
the problem.

Answer 6

Case 2

Question 7

Consider a rigid body rotating in a plane. We wish to determine the angular velocity
of the rigid body given the known velocities of points A and B on the rigid body. These
velocities are pointing in parallel, but opposite directions. The line joining points A and B
is perpendicular to the direction of the velocities. The figure below illustrates the setup of
the problem.

Answer 7

Case 3