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Physics, Astronomy & Cosmology / Force Exerted By Moving Objects
« on: 04/12/2007 22:44:51 »
How do you quantify the additional force exerted by an object due to its motion? An object at rest on a surface exerts a downward force equal to it's weight: F=ma, where "a" is gravity. Now drop that same object from a height, and there would appear to a force greater than the object's weight exerted. In fact, the object may now cause damage (dent, crack, etc.) to the surface whereas when it was at rest no damage was caused. The object's momentum (mass x velocity) at impact can easily be calculated, but what relation does the momentum have to the additional force exerted by the object due to its motion. To illustrate this more graphically, envision holding a sheet of paper horizontally, with a 50 gm object resting on top of it. To start with, the object is supported by the sheet of paper. Gradually increase the weight of the object (while maintaining the same surface contact area with the paper), and you will eventually reach a weight at which the object breaks through, let's say that weight is 200 gm. Now, start again with the 50 gm object and a new (identical) piece of paper, and drop the object onto the paper at small increments of height, and eventually you will reach the minimum height at which the 50 gm object will break through the paper. Now, how do I relate the two scenarios??