Question

Find volume of substance of mass 78g and density 7.8g/cm3.​

Answer 1

Answer:

Explanation:

Given,

Density = 7.8g/cm³

Volume = 100 cm³

We know, Mass = density × volume  

Then put values,

⇒7.8 × 100 = 780 g or 0.78kg

on Then we know,

Weight  = mg = 0.78 × 9.8 = 7.64 N

So, weight = 7.64 N

It fully submerge in water.  

∴ Volume of displaced water = volume of iron peace = 100cm³

∴ Mass of displaced water = density × volume of displaced water

                                         = 1.0×100 [ density of water = 1.0cm³]

                                         = 100g or 0.1kg

i n s t a g r a m

weight of water = mg

                        = 0.1×9.8  

                       = 0.98 N or 1 N

Buoyant force = weight of displaced fluid [ Archimedes  Principal]

∴ Buoyant force = 0.98 N

Then, weight of iron piece in water = weight in air - buoyant force

                                                       = 7.64 - 0.98

                                                       = 6.66 N

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Answer 2

Answer:

10 cm³

Explanation:

$volume \: = \: mass \: \div \: density$

V = 780/7.8 = 10 cm³

HOPE IT HELPS.....