For 10 points, name this device which was used to show rotation of the earth by Foucault.
The Jacobi elliptic functions can be used to calculate this device's kinetic equations. A T-shaped one is known as Rott's type of this, which like the double type, illustrates chaotic behavior. One can calculate the initial velocity of the bullet using gravitational potential energy with the ballistic one. An approximation of sin theta equals theta simplifies equations involving this device, such as calculating its period to be two pi times the square root of length over gravity. For 10 points, name this device which was used to show rotation of the earth by Foucault.
The Jacobi elliptic functions can be used to calculate this device's kinetic equations.
pendulum