Mass And Density Of Earth - Practice Questions & MCQ

• Mass of earth-

Using Newton’s law of gravitation we can estimate the mass of the earth

 

 mass of earth

 Gravitational constant

 

• Density of earth

As

Where density of earth

So

 

• Inertial mass

Also known as the mass of material of body which measures its inertia.

From  Newton’s second law of motion

So

Where 

inertial mass

external force

1.   Gravity has no effect on inertial mass.

2.   Inertial mass is independent of size, shape, and state of the body.

 

• Gravitational Mass-

It is mass which determines the gravitational pull acting upon it.

Let F= gravitational pull on a body of mass 

applying Newton’s law of gravitation

We have

So we get

Where Gravitational mass

Gravitational field intensity

            Tip-Spring balance measure gravitational mass.

• Mass (m)

 

1. It is the quantity of matter contained in the body.

2. Its SI unit- Kg

3. Its dimension is  

4.  It is a scalar quantity.

5. It Can never be zero

6. Its value does not change with g.

 

• Weight (W)

1. It is an Attractive force exerted by the earth on anybody.

2. S.I. Unit: Newton or Kg - wt 

3. Dimension- 

4. It is a vector quantity

5. It changes its value according to the value of g

6.  At and at the centre of earth g = 0, So W is equal to zero there.