ENGR 215 ~ Dynamics Sections 16.4

Absolute Motion Analysis A body subjected to general plane motion undergoes simultaneous translation and rotation. The motion can be completely describe by knowing Angular rotation of a line in the body The motion of a point on the body.

Absolute Motion Analysis We define these motions by using the rectilinear coordinate s to locate a position along its path. using the angular position coordinate θ to specify the orientation of the line. The two coordinates (s and θ) are then related using the geometry of the problem. Linear velocity and angular velocity are related by taking time derivates and applying the chain rule.

Lecture Example 1: The bar remains in contact with the floor and with Point A. If Point B moves to the right with a constant velocity vB, determine the angular velocity and the angular acceleration of the bar as a function of x.

Lecture Example 2: The bar is confined to move along the vertical and inclined planes. If the velocity of the roller at A 6 ft/s when θ=45°, determine the bar’s angular velocity and the velocity of the roller B at this instant.

Lecture Example 3: Find vG and aG