Slider Bar
Statement of the problem
This slider bar problem illustrates the relative velocity and acceleration
of two points on two rigid bodies. Various slider crank mechanisms
require an analysis procedure similar to this slider bar. The velocities
of different locations such as the pin-joint or mass center of a rod in
the system are of concern here. Also we are curious about the relative
motion of different points in the system, therefore we designate different
reference frames to observe the motion.
Exercises
Reference on the Ground
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By moving the Slider or input a number in the box, set a value of
angular velocity of bar 2, e.g. -2 rad/s.
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Select a reference frame on the ground by clicking on one of the
four buttons- Ground. If the system is out of the window, using
the Scroll Bars on the left-hand side and bottom of the window to
move it back.
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Let the program Run for a while then stop it. Watching
trajectories of different points. What do you find?
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Click on Reset and Erase Track, then you can choose
different reference frame let the program Run again.
Reference on Bar 1
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Select a reference frame on point A by clicking on the button- Bar
1. If the system is out of the window, using the Scroll Bars
to move it back.
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Let the program Run for a while then stop it. Notice
in particular the motion of Point P?
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Click on Reset and Erase Track, choose different reference
frame to Run the program again.
Reference on Bar 2
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Following the same procedure, you can choose the center of Bar 2.
Run the program. What do you find out?
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Can you give a simple conclusion about the relative motion of different
points by choosing different reference frame? Why are we interested in
the relative motion of different points in the system?
Think Twice
, Can you find the angular velocity of Bar 1?