Question

an object weighs 205 N in the air and it weighs 125 N when totally submerged in water.

Part A: determine density of object ?

(.......kg/m^3)

(I onlhy had 1 try left in mastering physics, hope you help me thanks)

Answer 1

Weight in the air W = 205 N

So, mass of the object, m = W/g = 205 / 9.8 = 20.92 kg

Weight in the water, W' = 125 N

So, loss in weight of the object in water = W - W' = 205 - 125 = 80 N

Suppose, V is the volume of the object.

Therefore. loss in weight of the object in water = weight of the displaced water

=> 80 N = V**g [where, = density of water = 1000 kg/m^3]

Therefore,

80 N = V*1000 kg/m^3 *9.8 m/s^2

=> V = 80 / (1000*9.8) = 0.00816 m^3

Therefore, density of the object = m/V = 20.92 / 0.00816 = 2562.7 kg/m^3 (Answer)