Force. (vector)

A force is a push or a pull, exerted by one object on another.

In SI force measured in N or kg.m/s2

It has a direction and a magnitude so it is vector

Force (F) = mass (m) x acceleration (a)

Force depends mass and

• Acceleration is directly proportional to force.
• Acceleration is inversely proportional to mass.

The three laws of motion

========================================

The resultant of two or more forces acting along the same line.

Case 1 (the resultant force = zero)

================================

Balanced forces have the same effect as No force at all which means No acceleration is done.

1)   At rest….If an object is at rest
This object will never move unless an external force acting on it.

The total sum of the force in opposite directions will be = zero.

2)   At Motion with constant speed…..

This object will never stop, decrease its velocity or increase it velocity unless an external force acting on it (e.g. friction with air or ground, gravitational force or breaking system or increasing the thrust force.)

The total sum of the force in opposite directions will be = zero.

========================================

The resultant of two or more forces acting along the same line.

Case 2 (the resultant force not equal to zero = unbalanced forces)

================================

Unbalanced forces cause the body to be

1)   At acceleration.

2)   At deceleration.

Unbalanced force = Net Force = mass x acceleration

Fnet = m x a