Conservation of Energy of an Interrupted Pendulum

AI Thread Summary
The discussion focuses on the conservation of energy in an Interrupted Pendulum setup, where a ball attached to a cord is released and interrupted by a peg. Key calculations involve determining the speed of the ball at the top of its circular path and finding the minimum distance required for the ball to complete a circle around the peg. Participants suggest using conservation of energy principles to solve these problems, emphasizing the importance of initial conditions and the forces acting on the ball. The conversation also questions whether the ball can complete a circle if the distance d is set to 0.5L. Overall, the thread highlights the application of physics concepts to analyze motion in a pendulum-like system.
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The studio explores the conservation of energy using the Interrupted Pendulum apparatus shown in (Figure 1). A ball is attached to a horizontal cord of length L whose other end is fixed. A peg is located at a distance d directly below the fixed end of the cord. The ball is released from rest when the string is horizontal, as shown in the figure, and follows the dashed trajectory in a fashion similar to a pendulum until the peg interrupts it, which causes the ball to suddenly follow a tighter circular trajectory.

Image: http://session.masteringphysics.com/problemAsset/1000232220/3/peg.jpg

1) If d = 0.75L, find the speed of the ball when it reaches the top of the circular path about the peg, in terms of L and g.

2) What is the minimum distance d_min (expressed as a fraction of L) such that the ball will be able to make a complete circle around the peg after the string catches on the peg? (Hint: what speed does the ball need to have at the top of its arc if it is to just barely continue to move in a circle?)

3) Will the ball be able to make a complete circle about the peg if d = 0.5L?

Attempt at solving the equation:

I'm not sure where to start, but I thought about using d=V_0*sqrt(m/k). Any explanations would be great! Thanks!
 
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Have you tried starting with the conservation of energy?
 
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