Question

Objects fall towards the earth because the earth pulls those. This pull is called ____ force.
A. contact.
B. muscular.
C. gravitational.
D. electrostatic.

Answer 1

Hint: In this question we have been asked to define the force with which the object is pulled by the earth. We know that any object when thrown upwards from the surface of the earth returns to the earth after attaining a particular height. The earth pulls the object with a force. This phenomenon was first observed by Sir Isaac Newton.

Complete answer:
In the given statement an object is pulled towards the earth with a particular force. Sir Isaac Newton observed the same thing when he saw an apple falling down the tree. He then started wondering about the force that pulls the objects towards earth. In the year 1687 Newton published a comprehensive theory about the same force. This was called a gravitational force. The gravitational force is always attractive. The gravitational force always pulls the objects towards itself. Due to this force, we can explain various other phenomena such as high and low tides. The gravitational force was considered to be the weakest force. However, after the discovery of the first black hole, it is said that gravitational force is stronger than other forces. According to Einstein Black holes are a point in space where the gravitational force is extremely strong. Nothing can escape from the event horizon of a black hole where gravitational pull is found to be large.

So, the correct answer is “Option C”.

Note: When objects fall on the surface of the earth, they attain a certain acceleration. This acceleration is known as acceleration due to gravity. The value of acceleration due to gravity denoted by g is found to be 9.8 m/squared second. The value of g depends on the height of the location from the earth's surface. The value 9.8 metre per second square is taken as the acceleration due to gravity at sea level. As we go above the sea level the acceleration due to gravity reduces.