# Concepts of Force and Motion

#### Academic Questions in PhysicsPlease check out our Test Your Knowledge page to see all Questions and Answers The rate of change of momentum is proportional to the applied force and will take place in the direction of that force. The above statement is attributed to _____. A. Albert Einstein B. Isaac Newton C. Galileo Galilei D. Neils Bohr E. Ernest Rutherford F. Marie Curie The Law of Inertia is also referred to as _____. A. 1st Law of Thermodynamics B. 2nd Law of Thermodynamics C. 3rd Law of Thermodynamics D. Newton's 1st Law of Motion E. Newton's 2nd Law of Motion F. Newton's 3rd Law of Motion The process whereby the velocity of an object increases and decreases over a period of time is best associated with the term _____. A. Speed B. Velocity C. Momentum D. Constant Velocity E. Acceleration F. Average Velocity The rate of motion is best referred to as _____. A. Speed B. Velocity C. Momentum D. Inertia E. Acceleration F. Constant Velocity Consider this expression below: A body X exerts a force FX on another body Y. In return, body Y exert a force FY back on body X. The forces FX and FY are equal in magnitude but opposite in direction. Putting the above expression into equation: FX = -FY Where FX is the action force FY is the reaction Force The above expression relates to _____. A. Theory of Force B. Force Postulate C. Einstein's proposal on Relativity D. Newton's 1st law of motion E. Newton's 2nd law of motion F. Newton's 3rd law of motion The tendency of a body to remain in a state of rest or in uniform motion is referred to as _____. A. tension B. uniform acceleration C. constant acceleration D. deceleration E. inertia F. velocity A change in the position of an object with reference to time is best described as _____. A. momentum B. displacement C. velocity D. acceleration E. direction F. motion The saying "what goes up on earth must come down" can be best attributed to _____. A. force B. motion C. mass D. acceleration E. average velocity F. constant velocity For a free trial, click here. Recommend to a school and get 25% commission for 6 academic terms

### Concept of Force:

Force is a vector quantity because it has both magnitude and direction.

By definition, any form of push or pull acting on an object is termed force.

You probably may have heard a saying that goes thus:

• what goes up must come down.

The above statement is true because the earth has a force acting on it. This force, (called the gravitational force of the earth) acts by pulling all things towards the earth.

In order to move away from the earth, there must be another constant force greater than the gravitational force or force of gravity.

Note: Aeroplanes and Jets move away (fly) from the earth and remains in the sky because the constantly applied force in them is greater that the earth's gravitational force.

In another instance, when you jump, you apply a force; but since this applied force isn’t constant, the force of gravity present on earth eventually bring you back to earth's suface.

Note: Force as a quantity is measured in Newtons (N). This is in honor of Sir Isaac Newton for the great work he has done.

Force can be balanced or unbalanced. To summarize this:

An apple hanging on a tree has a balanced force.

An apple falling from a tree has an unbalanced force.

### Force and Motion:

Sir Isaac Newton presented the laws of motion (which will later be accredited to his name) in 1968. These "motion laws" of Newton explains the relationship between the forces acting on a body and the motion of the body.

Recall that motion refers to a change in the position of an object with reference to time.

As an instance, a pen resting on a table will continue to remain on the table unless it is pushed or pulled by something. This push or pull with the tendency of making the pen move away from its exact position is known as force.

Note: Force exists as a result of an interaction between two objects. From the above instance, if nothing interacted with the pen on the table, then the pen will continually remain on the table.

If there is no interaction between objects, force will never be experienced.

With the above explanation on force and motion, we can now understand more easily the Newton's laws of Motion. Alfred Ajibola is a Medical Biochemist, a passionate Academician with over 7 years of experience, a Versatile Writer, a Web Developer, a Cisco Certified Network Associate and a Cisco CyberOps Associate.

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