Question

WHAT DO YOU MEANT BY FREE FALL

Answer 1

DEFINITION OF FREE FALL

When an object falls from any height under the influence of gravitational force only, it is known as free fall.

In the case of free fall no change of direction takes place but the magnitude of velocity changes because of acceleration.

This acceleration acts because of the force of gravitation and is denoted by ‘g’. This is called acceleration due to gravity.

LET'S SEE AN EXPRESSION FOR ACCELERATION DUE TO GRAVITATION 'g' :-

Let mass of the object put under free fall = m.

And acceleration due to gravity = g.

Therefore, according to Newton’s Second Law of Motion which states that Force is the product of mass and acceleration,

F = m x g -(i)

Now, according to Universal Law of gravitation,

$F = G\frac{Mm }{d^{2} }$ ----------------(ii)

Thus, from above two expressions, we get

$mg = G \frac{Mm}{d^{2} }$

⇒    $g = \frac{GMm}{d^{2}m }$    ⇒  $g = \frac{GM}{d^{2} }$  ----------(iii)

Where, g is acceleration due to gravity,

G is the Universal Gravitational Constant.

M is the mass of earth.

And d is the distance between object and centre of earth.

HOPE IT WILL HELP YOU

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Answer 2

Answer:

When an object falls from any height under the influence of gravitational force only, it is known as free fall.

In the case of free fall no change of direction takes place but the magnitude of velocity changes because of acceleration.

This acceleration acts because of the force of gravitation and is denoted by ‘g’. This is called acceleration due to gravity.

LET'S SEE AN EXPRESSION FOR ACCELERATION DUE TO GRAVITATION 'g' :-

Let mass of the object put under free fall = m.

And acceleration due to gravity = g.

Therefore, according to Newton’s Second Law of Motion which states that Force is the product of mass and acceleration,

F = m x g -(i)

Now, according to Universal Law of gravitation,

F = G\frac{Mm }{d^{2} }F=G

d

2

Mm

----------------(ii)

Thus, from above two expressions, we get

mg = G \frac{Mm}{d^{2} }mg=G

d

2

Mm

⇒ g = \frac{GMm}{d^{2}m }g=

d

2

m

GMm

⇒ g = \frac{GM}{d^{2} }g=

d

2

GM

----------(iii)

Where, g is acceleration due to gravity,

G is the Universal Gravitational Constant.

M is the mass of earth.

And d is the distance between object and centre of earth.

HOPE IT WILL HELP YOU

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