Question

(1)Types of force with eg. (2)Write Newton's laws & equations.

Answer 1

Newton's law

Law I: Every body persists in its state of being at rest or of moving uniformly straight forward, except insofar as it is compelled to change its state by force impressed.[14][b]

Law II: The alteration of motion is ever proportional to the motive force impress'd; and is made in the direction of the right line in which that force is impress'd.[15][c]

Law III: To every action there is always opposed an equal reaction: or the mutual actions of two bodies upon each other are always equal, and directed to contrary parts

Type of Force

(and Symbol)

Description of Force

Applied Force

Fapp

An applied force is a force that is applied to an object by a person or another object. If a person is pushing a desk across the room, then there is an applied force acting upon the object. The applied force is the force exerted on the desk by the person.

Gravity Force

(also known as Weight)

Fgrav

The force of gravity is the force with which the earth, moon, or other massively large object attracts another object towards itself. By definition, this is the weight of the object. All objects upon earth experience a force of gravity that is directed "downward" towards the center of the earth. The force of gravity on earth is always equal to the weight of the object as found by the equation:

Fgrav = m * g

where g = 9.8 N/kg (on Earth)

and m = mass (in kg)

Normal Force

Fnorm

The normal force is the support force exerted upon an object that is in contact with another stable object. For example, if a book is resting upon a surface, then the surface is exerting an upward force upon the book in order to support the weight of the book. On occasions, a normal force is exerted horizontally between two objects that are in contact with each other. For instance, if a person leans against a wall, the wall pushes horizontally on the person.

Friction force

Ffrict

The friction force is the force exerted by a surface as an object moves across it or makes an effort to move across it. There are at least two types of friction force - sliding and static friction. Though it is not always the case, the friction force often opposes the motion of an object. For example, if a book slides across the surface of a desk, then the desk exerts a friction force in the opposite direction of its motion. Friction results from the two surfaces being pressed together closely, causing intermolecular attractive forces between molecules of different surfaces. As such, friction depends upon the nature of the two surfaces and upon the degree to which they are pressed together. The maximum amount of friction force that a surface can exert upon an object can be calculated using the formula below:

Ffrict = µ • Fnorm

Air Resistance Force

Fair

The air resistance is a special type of frictional force that acts upon objects as they travel through the air. The force of air resistance is often observed to oppose the motion of an object. This force will frequently be neglected due to its negligible magnitude (and due to the fact that it is mathematically difficult to predict its value). It is most noticeable for objects that travel at high speeds (e.g., a skydiver or a downhill skier) or for objects with large surface areas. Air resistance will be discussed in more detail in Lesson 3.

Tension Force

Ftens

The tension force is the force that is transmitted through a string, rope, cable or wire when it is pulled tight by forces acting from opposite ends. The tension force is directed along the length of the wire and pulls equally on the objects on the opposite ends of the wire.

Spring Force

Fspring

The spring force is the force exerted by a compressed or stretched spring upon any object that is attached to it. An object that compresses or stretches a spring is always acted upon by a force that restores the object to its rest or equilibrium position. For most springs (specifically, for those that are said to obey "Hooke's Law"), the magnitude of the force is directly proportional to the amount of stretch or compression of the spring.

Answer 2

Answer:

Explanation:

(1) Types of FORCE :

• Contact Force : These are forces which require contact with other objects. eg. Muscular Force, Frictional Force etc..
• Non-Contact Force : These are forces which doesn't require contact with other objects.  eg. Gravitational Force, Magnetic force etc..

(2) Newton's Laws and Equations

• According to Newton's first law of motion, an object either remains at rest or continues to move at a constant velocity, unless  a force is applied.
• According to Newton's second law of motion, the sum of the forces F on an object is equal to the mass m of that object multiplied by the acceleration a of the object: F = ma.
• According to Newton's third law of motion, when one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body.  

         Fa = -Fb