Question

An apple falls from a tree because of gravitational attraction between the earth and the apple. If ${\mathrm{F}}_1$ is the magnitude of force exerted by the earth on the apple and ${\mathrm{F}}_2$ is the magnitude of force exerted by the apple on the earth, then

• A. ${\mathrm{F}}_1$ is very much greater than ${\mathrm{F}}_2$
• B. ${\mathrm{F}}_1$ is only a little greater than ${\mathrm{F}}_2$
• C. ${\mathrm{F}}_1$ is only a little greater than ${\mathrm{F}}_2$
• D. ${\mathrm{F}}_1$ and ${\mathrm{F}}_2$ are equal

Answer 1

The correct option is D

${\mathrm{F}}_1$ and ${\mathrm{F}}_2$ are equal

Explanation for correct option:

Option (d): ${\mathrm{F}}_1$ and ${\mathrm{F}}_2$ are equal

• Newton's third law of motion claims that when one body exerts a force on another, the first body experiences a force equal in magnitude but in opposite direction.
• Because Newton's third law of motion is followed by Newton's law of gravity, ${\mathrm{F}}_1$ and ${\mathrm{F}}_2$ are equal.
• When one object applies a force to another, the second item reacts by applying an equal and opposite force to the first.
• The action of is the force of gravity acting downward (${\mathrm{F}}_1$) on the apple by the earth.
• The force exerted by the apple on the earth is the reaction (${\mathrm{F}}_2$).

Hence, ${\mathrm{F}}_1$ and ${\mathrm{F}}_2$ are equal