Question

The earth and the moon are attracted to each other by gravitational force. Does the earth attract the moon with a force the moon attracts the earth? Why?

Answer 1

Hint : Every object in the universe is under the force of the gravitational. Any two objects attract each other and are directly proportional to the product of the mass and inversely proportional to the square of distance between the two. Here we will use the formula - $g = G\dfrac{M}{{{R^2}}}$ where g is the gravity of acceleration and G is the gravitational force.

Complete Step By Step Answer:
Let us assume that the “m” and “M” are the mass of the moon and the Earth respectively which are separated with the distance “r”.
Force of attraction which Earth exerts on the Moon can be given by ${F_e} = \dfrac{{GMm}}{{{r^2}}}$
And the force of attraction which Moon exerts on the Earth can be given by ${F_m} = \dfrac{{GMm}}{{{r^2}}}$
Therefore, the Earth attracts the Moon with the same force by which the Moon attracts the Earth.
Also, by the gravitational force which is an internal force of the attraction between the two bodies and hence they have to be equal in magnitude.

Note :
Remember the difference between the g (gravitational acceleration) and the G (Gravitational constant). Since in G only magnitude is important it is the scalar quantity whereas, in g both the magnitude and the direction are important, and therefore it is vector quantity. The value of “G” remains constant throughout the globe whereas, the value of “g” changes from every place on the planet. Go through certain basic parameters and the physical quantities to solve these types of word problems.