What is the magnitude of the gravitational force between the earth and 1 kg object on its surface? (Mass of the Earth = 6 x 104 kg and radius of earth is 6.4 x 106 m)
What do you mean by buoyancy?
The upward force acting on a body immersed in a fluid is called upthrust or force of buoyancy. The phenomenon is called buoyancy.
The magnitude of buoyant force depends upon the density of the fluid.
When does an object float or sink when placed on the surface of water?
(i) An object sinks in water if its density is greater than that of water. Upthrust of water on an object is less than the weight of the object. Hence, it sinks.
(ii) An object floats on water when its density is less than that of water. When the upthrust of water on the object is greater than the weight of the object, the object floats.
Gravitational force acts on all objects in proportion to their masses. Why, then, does not a heavy object fall faster than a light object?
If F be the gravitational force on a body of mass m, then
Clearly, F ∝ m but g does not depend on m. Hence, all bodies fall with the same rapidness when there is no air resistance.
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