Calculating Velocity and Acceleration of Ball from Child A

AI Thread Summary
To calculate the velocity and acceleration of ball B as observed by child A on the Merry Go Round (MGR), one must consider the angular velocity of the MGR and the linear velocity of both child A and the ball. The angular velocity of the MGR is 0.5 rad/s clockwise, while child A runs at 0.4 m/s in the same direction. The ball is thrown at 10 m/s towards the center of the MGR from a distance of 4.5 m. The solution involves combining the motions of child A, the MGR, and the ball to determine the perceived trajectory, which requires understanding the initial positions and velocities in a coordinate system. The discussion highlights the complexity of superimposing these motions to accurately describe the ball's trajectory from child A's perspective.
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Homework Statement


A child A is on a Merry Go Round that is turning at an angular velocity of 0.5 rad/s in the
clockwise direction. A ball B thrown from another child who is 4.5 m from the center of the MGR has a velocity of 10m/s and directly aimed at the center of the MGR as shown in the figure. Now, let us assume that the child A is running along the edge of the MGR at 0.4m/s in the clockwise direction with respect to the MGR. Find the velocity and acceleration of the ball seen from the child A.


Homework Equations



I know, W,A = W,MGR + W,A/MGR where W=angular velocity

And i belive, W,A/MGR = 2pi/(time for A to make one rotation)

The Attempt at a Solution



I am not sure how to calculate the time for A to make one rotation
 
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To me this a very intersting problem, and have no knowledge whatsoever from experience on similar problems, so likely of no use. Also I see no picture nor even understand what you have posted.
My limited undertanding:

first, the ball B will hit the center target. Thrower is not in motion nor is the center of the MGR. Nor is the ang velocity of the MGR important, or our A child, for that matter except insofar as we have a total ang velocity. So the perspective from child a is really a superposition of his motion, the MGR's and the balls. The first two add in simple way.

so if we could generate a superposition of spatial coordinates as a function of time for both ball and child, then we could accurately describe motion as seen by the child?

Then if childs place in space C(x,y)= R*(cos(wt) + sin(wt)) and the ball along the x coordinate as 4.5-10*t, then there should be a way to portray the combined motions. But this is where I get stuck, not knowing initial x,y of child how to proceed? Obviously at 12o'clock looks much different to observer than at 6. But in general,

Vx=d(C(x,y))/dt+10,
Vy=d(C(x,y)/dt (these are partials obviously) so knowing both x' and x", y' and y" we can map out perceived trajectory. I very much doubt this cumbersome notation is what is asked for, just wanting to understand, and I still don't get it, for instance

If I were to translate these to words, I would think along the x-axis the ball either accelerates briefly, then still (depending on R and w vs 10) and then slows or vice versa, while on the Y depending on which starting point I chose, say 12noon, the overall motion would be like that of a heat seeking missile and assuming i could make the 1/4 turn before getting it between the eyeballs,would then veer to the left and slow down. There must be a formal way of mixing these frames of reference? Help.
 
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