When a body is partially or completely immersed in a fluid, the fluid exerts an upward force on the body equal to the weight of the fluid displaced by the liquid.

Given m = 4 kg,

p = 4000 kg m^-3,

a = 1000 kg m^-3,

g = 10 m s^-2,

Wa = ?

Weight of ball in air = 4 x 10 = 40 N

Loss in weight = Density of water x (Mass of ball / Density of ball) x g

Or Loss in weight = 1000 x (4/4000) x 10 = 10 N

Apparent weight of ball in water=40 -10=30 N.

# State Archimedes' Principle. A ball weighing 4 kg of density 4000 kg m^-3 is completely immersed in water of density 1000 kg m^-3. Find the apparent weight of the ball in water. (g = 10m s^-2)

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