PURPOSE: Newton's second law applied to rotation about a fixed point.
DESCRIPTION: Two boards are fixed together by a hinge at one end so as to allow them to fold together. One board is layed flat on the table and the other board is propped up by a stick, as shown, with a ball balanced on a golf T attached to the end of the board. When the stick is pulled away and the board is released to free fall, it is torqued about the hinge and rotates as it falls. Thus, the rotation force cause the end below the ball to accelerate faster than the ball. The ball falls into the cup.
EQUIPMENT: Stick, ball and cup apparatus stored in mechanics.
SETUP NOTES: Practice.
References:
Philip A. Constantinides, Experiments on Torque, Angular Acceleration and Moment of
Inertia, AJP 7,
254-257, (1939).
Carl A. Ludeke, Experimental Examples in Dynamics, AJP 9, 162-166, (1941).
Julius Sumner Miller, On Demonstating A Classical Problem In Analytical Mechanics, AJP 20,
455-456,
(1952).
Richard M. Sutton, Some teasers for conclusion jumpers, AJP 21, 658 (1953).
Wallace A. Hilton, Free Fall Paradox, TPT 3, 323-324, (1965).
George W. Ficken, Jr., "Falling" Faster than g, AJP 41, 1013-1015 (1973).
Albert A. Bartlett, Falling Chimney Apparatus Modification, TPT 13, 435-437, (1975).
Jerry L Adams, Acceleration Greater Than "G", TPT 20, 100-101, (1982).
W.M. Young, Faster Than Gravity!, AJP 52, 1142, (1984).
W.F.D. Theron, the "Faster Than Gravity" Demonstration Revisited, AJP 56,
736-739, (1988).
Updated by Jun Qi in 3/13/2000