Relative velocities of rigid bodies

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SUMMARY

The discussion focuses on calculating the velocities of a triangular body undergoing rotation, specifically at the moment when theta equals 90 degrees and theta_dot is 5 rad/s, with beta at 45 degrees. The equations used include vB = vE + w x rB/E and vB = vA + w x rB/A, leading to the determination of vB as -10i cm. The user expresses confusion regarding the appropriate angular velocity to use for the calculation, questioning whether to apply theta_dot or a different angular velocity due to the angle beta.

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Homework Statement



A triangular body changes orientation as the suspporting links rotate. At the moment shown, theta = 90 deg, theta_dot = 5 rad/s, and beta = 45 deg. Determine vA and the angular velocity of the triangular body.
rB/C = 2j cm and rB/A = 5i cm

Points E and D are fixed. theta is the angle made between horizontal and BE. beta is angle made between horizontal and AD.

Homework Equations



vB = vE + w x rB/E
vB = vA + w x rB/A

The Attempt at a Solution



vB=vE + w x rB/E
vB=0 + 5k x 2[]j[/b]
vB=-10i

vB=vA + w x rB/A
-10i = vA + w x 5j


I am stuck at this point because I am not sure if I should use theta_dot for this w because AD is at a different angle (beta). And if I do need to use a different w (which would be beta_dot how would I find it without knowing the length of AD.
 
Last edited:
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Where's the diagram?
 
Shooting star said:
Where's the diagram?

ya.. please if diagram is to be provided.. do not omit it.
 

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