Cannonball+Drop

During the 1600’s people thought that the heavier an object was the faster it fell. Galileo, a famous mathematician discovered that this belief about falling objects was false. Instead, he theorized that all fall at the same rate regardless of weight. To prove his hypothesis, so it is said, Galileo took two cannonballs to the top of the Leaning Tower of Pisa. Both balls were spherical, but one was heavier than the other. With a crowd of on lookers, Galileo dropped the two cannonballs at exactly the same time from the same height. Galileo repeated this experiment with cannonballs of various weights, but they would all hit the ground at the same time. This event set the stage for Isaac Newton’s interpretation of gravity in the following century. Back

[|Trajectory Ellen Show] Does horizontal velocity affect how fast it falls?

Also, why don't we feel the Earth spin? Video of object dropped from a horse: http://ca.pbslearningmedia.org/resource/phy03.sci.phys.mfw.galthought/galileos-thought-experiment/

Galileo explained why the spinning Earth doesn’t move under you when you jump. This is the same reason you don’t feel the Earth spinning. Galileo reasoned that a person jumping from a spinning Earth is like a object dropped by a rider on a horse (representing the Earth) moving with a constant velocity From the rider’s point of view, the object would appear to drop vertically, straight to the ground, accelerating downwards the whole time. A bystander who is stationary relative to the ground would see the rider, horse and projectile whoosh past and, like a projectile, the dropped object would appear to follow a parabolic trajectory.

Galileo argued that the parabolic motion of the projectile was made up of two separable parts: its dropping as seen by the rider, and its constant horizontal velocity (which is the same as that of the horse).

Galileo then argued that the Earth doesn’t zoom away under your feet because at the moment you jump upwards you already have the same horizontal component of velocity as the Earth’s surface. Relative to the Earth’s surface, your horizontal velocity is zero and so you land on the same spot.

More on Galileo http://www.daviddarling.info/encyclopedia/G/GalileoG.html