# Tagged With "gravitational potential energy"

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#### Rotational Dynamics of a Falling Meter Stick

There is a well-known problem in rotational dynamics that involves a meter stick. The meter stick is held in a vertical position with one end on the floor. It is then released so that it falls to the floor. The end initially on the floor is not allowed to slip during the fall. Students are asked to derive an equation that predicts the angular velocity of the meter stick just before it hits the floor. The derivation involves many physics concepts including gravitational potential energy,...

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#### Investigating the "Spinning Coin" (Euler Disk) Problem

Most everyone has spun a coin on its edge on a table top, and many find the result quite fascinating. The coin gradually begins to fall on its side while spinning, makes a whirring sound with increasing frequency the longer it spins, and then abruptly stops. The Swiss physicist, Leonhard Euler, studied this back in the 1700's. An educational toy, referred to as Euler's disk can now be purchased on-line and in hobby shops specializing in science. Such disks have been carefully engineered to...

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#### Re: Investigating the "Spinning Coin" (Euler Disk) Problem

Rich- Your lab made me think of a dynamics problem I had in grad school. I dug up my old textbook so I could share. We analyzed the motion of a similar spinning disk. It was one of the toughest dynamics problems I ever had to solve. You have to solve for a system of equations of the angular acceleration of the spinning disk and the linear acceleration of the disk's center of mass. Eventually the system of equations gets too cumbersome to solve by-hand and so we used a program called...