Question

When you and your friend push a heavy table in the same direction, it becomes easier to move. This is because:
A. The net force is the sum of forces
B. The net force is the difference of forces
C. The table becomes lighter
D. Friction reduces

Answer 1

Hint: A force can be classified as a pull or a push that an object experiences as a result of its contact with another body. A force that is applied to an object by an individual or another object may have a multitude of impacts on the object on which the force is applied. A force is working on the table in this case.

Complete step by step answer:
Force is the agent which can work from outside, that has the ability to change the condition of rest or motion of a specific entity. It has a magnitude, but also provides direction. The direction of the force is the direction in which the applied force acts on an entity, and when such a force is applied, the point at which it is focused is the point where force is applied.

Here we see that two people are pushing the same table so both of the individuals have contact with the table. So clearly since force can be a ‘push’, both the individuals are putting force on the same table. We are given the condition that both of them are pushing the table in the same direction so this means that the force applied by them can be added to get the effective force experienced by the table.

Examine each of the given options carefully and understand their relation in terms of pushing the table in order to find out the right option:
Option (A) ‘the net force is the sum of forces’ is the correct option. When two people, in this case you and a friend together cause motion (push) to a heavy table, causing it to move in the same direction, the force exerted by both of you is incorporated or added. As a result, the applied forces get summed up to form a greater force. This causes the table to move with ease. So it is correct to say that the net force is taken into consideration.

Option (B) ‘the net force is the difference of forces’ is an incorrect option. Such a case where the difference of forces is considered as the net force is when the force applied by the individuals are on the same object but in two opposite directions. Here since they have mentioned that the people are applying force toward the same direction, we do not need to take a difference of forces. So this option can be rejected.

Option (C) ‘the table becomes lighter’ is an incorrect option. When two people push a table, it does not bring about any change to the size or mass of the table, the table remains the same. The external force is able to move the table and not change its weight. So the table will not become lighter as the total weight of the table is the same no matter the number of people applying force on it. So we may reject this option.

Option (D) ‘friction reduces’ is an incorrect option. The resistance provided by materials that come into contact with each other while moving over one another is said to be friction. Friction can only reduce if the surfaces of either the ground or the table in this case become smoother and not when the force applied by two people on the table. Since the push by the individuals has no relation to friction we may reject this option.

Therefore the correct answer is option A.

Note:The application of force has a variety of consequences, some of which are mentioned below. Force may cause motion to a still or resting body. It has the ability to either halt or delay a moving body. It has the ability to increase the speed with which a moving body is travelling. It may also adjust the form and size of a moving body as well as its speed.