Relative Motion: Solving Kinematic Problems with Multiple Moving Objects

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SUMMARY

The discussion focuses on solving kinematic problems involving multiple moving objects, specifically boats and a missile. Participants emphasize the importance of using kinematic equations for each dimension and finding the relative velocities of the objects involved. The key takeaway is that to determine the missile's velocity in the lake's reference frame, one must subtract the velocity of boat A from the missile's relative velocity to boat B. This approach allows for treating the missile's motion as a standard projectile motion problem.

PREREQUISITES
  • Kinematic equations for motion analysis
  • Understanding of relative velocity concepts
  • Projectile motion principles
  • Reference frames in physics
NEXT STEPS
  • Study kinematic equations in two dimensions
  • Learn about relative velocity in different reference frames
  • Explore projectile motion problems in detail
  • Practice solving complex motion problems involving multiple objects
USEFUL FOR

Students in physics, educators teaching kinematics, and anyone interested in mastering relative motion concepts in mechanics.

btbam91
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[PLAIN]http://img811.imageshack.us/img811/4435/relativemotion.jpg

I'm having trouble on figuring out on how to go about this one.


I know that I have to use the kinematic equations for each dimensions, find time, and set the x components equal to each other, but the relative velocity of the missile is throwing me off.


Thanks for the help!
 
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In boat A's reference frame, boat B's velocity is Vbj, so what is boat B's velocity in the lake's reference frame?


Now do the same thing for the missile.

Once you have the missile's velocity in the lake's reference frame, you can solve the problem like a projectile motion problem.
 
So the missile velocity is relative to an observer on a?

So to find it's absolute velocity (with respect to the lake)

I do Vm-Va=the given relative missile velocity and solve for Vm?
 
I believe the problem is giving you the missile velocity relative to b
 
Yeah, it was (I asked my professor to clarify) and I was able to successfully solve the problem! Thank you!

But I do have one more problem that is a head scratcher!
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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