A penny is the onecent coin in United States. It equals onehundredth of a US dollar. The weight of a penny is about 2.5 grams, so the weight of 100 pennies must be equal more less
http://answers.ask.com/Reference/Other/what_is_the...

The number of pre1982 pennies that equal 100 grams is about 32. Th...
http://www.chacha.com/question/howmanypenniesto...

A U.S. penny weighs 2.50 grams. 100/2.50 = 40. There are 40 pennies in 100g. .
http://answers.yahoo.com/question/index?qid=201308...

1. Divide 100, the weight you wish to float, by 28,316.847, the weight in grams of 1 cubic foot of water. The result, 0.00353 equals the percentage of 1 cubic foot that the hull's
http://www.ehow.com/how_10073975_makeboatfloats...
