## Monday, 25 June 2012

### Buoyant Force

Explanation: When the object is removed, the volume that the object occupied will fill with fluid. This volume of fluid must be supported by the pressure of the surrounding liquid since a fluid can not support itself. When no object is present, the net upward force on this volume of fluid must equal to its weight, i.e. the weight of the fluid displaced. When the object is present, this same upward force will act on the object. The net force on the object is given by, * When the density of the object is less than that of the fluid, the net force will be upwards and the object will rise. A Helium filled balloon is a good example. Floating Objects: When an object is floating, the net force on it will be zero. This happens when the volume of the object submerged displaces an amount of liquid whose weight is equal to the weight of the object. A ship made of steel can float because it can displace more water than it weighs. Thus the fraction of a floating object that is submerged stand in ratio to the density of the object to the density of the fluid. For objects with a vertical wall around the outside edge like a rectangle, we can reduce the above equation even farther. Check us out at http://www.tutorvista.com//videos