The Science of Energy

in that the vis viva of an object depended on both its mass and on its velocity. Several scientists, including the Dutchman Willem s’Gravesande (1688–1742) and the Marquise du Châtelet, Gabrielle de Breteuil (c.1700–1749), were impressed by Leibniz’s idea and carried out experiments to test it.

S’Gravesande built a variety of machines to experiment with motion, such as one in which a moving metal ball on a thread was made to strike a stationary similar ball. By knowing the masses of the balls and their velocities before and after the collision, s’Gravesande could calculate how much vis viva was in each ball. It seemed that the vis viva could be transferred almost entirely from the moving ball to the stationary one. One of the most famous English scientists, Isaac Newton (1642–1727), made many

An object accelerates rapidly when it is free to fall. Galileo found that, whatever the

contributions to the study of energy and forces. Among Newton’s greatest contributions were his laws of motion , describing the way objects move. In mass of the object, it always accelerates at the same rate.

doing so he built on work done by Galileo over a hundred years earlier. The science of moving objects was brought to a peak by Newton, whose laws could be used to explain everything from an arrow travelling towards its target to the motion of the Moon around the Earth.

Find out about a device known as “Newton’s cradle.” How does it work, and what does this device demonstrate about momentum and energy? RESEARCH PROJECT

S’Gravesande investigated the amount of vis viva that could be passed on when one ball collided with another.

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