Question

Animals make use of __________ to carry out their physical activities and other tasks.
A. contact force
B. non-contact force
C. force of friction
D. muscular force

Answer 1

To answer this question, we need to understand the meanings and definitions of all the kinds of force mentioned in the options and then, we can be able to relate the correct option with that of the given question.
Force is said to be applied whenever there is a change in the state of rest or motion in the body.

Complete step-by-step answer:
The concept of the force is given by the 3 Newton’s laws of motion. They are:

First Law : When a body is at rest or moving at an uniform speed, it will remain at rest or keep moving in a straight line at the same uniform speed, unless it is acted upon by an external force.

Second Law: The force applied on the body is equal to the rate of change of momentum and the direction is along that of the acceleration of the body.
F = ma
where m is the mass and a = acceleration

Third Law: For every action, there is an equal and opposite reaction.

So, we can see that in these three laws, we can completely define the force. The first law gives us a qualitative description of the force and the second law gives us the quantization of the quantity of force.

There are four kinds of force, given in this question. Let us examine the definitions of these forces and understand them.

1. Contact force: It is a force that acts due to the presence of contact between the two surfaces.
Example – Frictional force
2. Non-contact force: It is a force that acts without the contact between the two surfaces.
Example – Electromagnetic force, Gravitational force
3. Frictional force : This force arises due to the obstruction offered by the surface to the flow of an object on the surface.
4. Muscular force : The muscular force is the force that is generated inside the body of animals due to the conversion of the chemical energy in their bodies to the mechanical energy. The mechanical energy , so converted, is used to apply a force from the inside of the body to move the muscles in the body such as limbs, heart and other muscles etc.

Hence, we can say that the force that the animals use to carry out their physical activities is the muscular force.

Hence, the correct option is Option D.

Note: There are two kinds of movements by the muscles – Voluntary and involuntary. Voluntary muscles are used for the movement by the will of the animal such as movement, walking, running and flying. Involuntary muscle movement includes the ones that are not under the control of the animal’s will such as the movement of heart.