Question

A 20 kg piece of metal displaces 7.8 L of water when submerged. Find the density (kg/m^3)

A 2.3 m-tall barrel is filled with water (with a weight density of 2127N / (m ^ 3) ). Find the water pressure (in kPa) on the bottom of the barrel

Find the force of gravity between a object (mass = 2.9 kg) and another planet (mass=7.6*10^ 23 kg) when the planet at its closest to Earth \ d/stance=1.2 x 10^ 10 m)

Find the force of gravity between a planet (mass=5.9*10^ 24 kg ) and the Sun (mass=2.0*10^ 30 kg) . (The average planet-Sun distance is Earth (dlstanc theta=9.0 x 10^ 19 m) Express your answer to two significant figures and include the appropriate units.

A 29 kg plece of metal displaces 1.9 L of water when submerged. Find the density (in kg/m3) Express your answer to two significant figures and include the appropriate units.

Answer 1

1)

Given data,

Mass = 20 kg

Volume = 7.8 L

= 7.8 x 10^-3m³

We know that,

Density = Mass / Volume

= 20 / 7.8 x 10^-3

= 2.56 x 10³ kg / m³

2)

We know that,

Water pressure = weight density x depth

= 2127 N / m³ x 2.3 m

= 4892.1 N / m²

= 4892.1 K Pa

3)

Given data,

d/stance = 1.2 x 10¹⁰ m

mass , m₁ = 2.9 kg

mass m₂ = 7.6 x 10²³ kg

We know that,

F = Gm₁m₂ / r²

= 6.67 x 10^-11 x 2.9x 7.6 x 10²³ /  ( 1.2 x 10¹⁰ )²

= 1.47 x 10¹⁴ / 1.44 x 10²⁰

= 1.02 x 10^-6 N