Simple problem about relative motion.

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SUMMARY

The discussion revolves around a physics problem involving two spheres connected by a 10-meter rod rolling down and up 45-degree inclines. At a specific moment, the sphere rolling down has a velocity of 2 m/s and an acceleration of 3 m/s². The key equations used include the relationship between the velocities of the spheres and the angular velocity of the rod, expressed as VB = VA + ω × rB/A. The participants seek clarification on the calculations and the correct interpretation of the angular velocity and position vectors.

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ParrotPete
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Homework Statement


A body consisting of two spheres attached by a 10 meter solid long rod is rolling down a 45 degree incline at one end while rolling up a 45 degree incline on the other end.
At the instant when the connecting rod is horizontal the sphere rolling down has the velocity 2 m/s down the incline and the acceleration 3 m/s^2 down the incline. At this time, what is the velocity of the sphere rolling up and what is the angular velocity of the rod?

Homework Equations



VB = VA+ωXrB/A

The Attempt at a Solution


VA=2*(cos(45)*ei-sin(45)*ej
VB = VB*(cos(45)*ei+sin(45)*ej)
rA/B= 10*ei
ω=ω*ez
Doing the calculations
VB cos(45) = cos(45)
VB*sin(45) = -2*sin(45)+10ω

What am I doing wrong?
 
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ParrotPete said:
VA=2*(cos(45)*ei-sin(45)*ej
VB = VB*(cos(45)*ei+sin(45)*ej)
I guess that's VB = vB*(cos(45)*ei+sin(45)*ej), to avoid the pun.
rA/B= 10*ei
ek, perhaps?
ω=ω*ez
What's ez? Do you mean ei?
Doing the calculations
VB cos(45) = cos(45)
You've lost me - where did that come from?
 

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