ballistic pendulum
Datecirca 1980
Inventory Number2006-1-0078
ClassificationDemonstration Device
Subject
User
Department of Physics, Harvard University
founded 1884
Cultural Region
Place of Origin
Dimensions21 × 11.5 × 16.3 cm (8 1/4 × 4 1/2 × 6 7/16 in.)
Material
DescriptionBallistic pendulum. Painted cylinder, most likely made of wood and filled with clay, sand, or some other material. The filling gives it considerable weight. On top and bottom are caps of wood ringed with brass. Caps are fastened to device with L-shaped slots on the brass rings into which fit pegs and screws distributed around the circumference of the cylinder. Nuts on the screws hold the cap. The cylinder is most likely filled with clay, sand, or some other heavy material.
In the middle of the cylinder around the circumference are four slotted-head screws. On one side of the cylinder toward each end are metal strips fastened by four screws. Each strip has a brass rod soldered on perpendicularly. It also has two pieces with holes by which the device may be hung.
In the middle of the cylinder around the circumference are four slotted-head screws. On one side of the cylinder toward each end are metal strips fastened by four screws. Each strip has a brass rod soldered on perpendicularly. It also has two pieces with holes by which the device may be hung.
Signedunsigned
Inscribedhandwritten on side of cylinder: A / 8E / B
FunctionIllustration of conservation of momentum. Determining the velocity of a projectile by measuring the distance traveled by the pendulum. The pendulum would be attached to strings and filled with clay or sand. A projectile would be fired at the pendulum and transfer its momentum to it. The pendulum would move forward and up. The distance the pendulum traveled, as well as the masses of the projectile and the cylinder, would be used to calculate the initial velocity of the projectile.
Beckman Instruments, Inc.
Date: circa 1955
Accessories: instructions attached to underside of box lid
Object number: 1996-1-0276
George Erle Beggs
Date: early 20th-mid 20th Century
Accessories: 6 deformeter gauges;
22 plugs;
2 cylindrical plastic boxes containing screws and metal strips for fastening the ends of the structure;
metal stylus;
2 metal pins;
2 celluloid wedges;
1 rectangular celluloid piece with a wedge coming out of one end
Object number: 1999-1-0064
