What is System of Forces with Practical Examples

What is System of Forces?

When two or more forces act on a body, they are called to form a system of forces.
There are various systems of forces mentioned below with their day-to-day examples.

Collinear Forces:

Collinear forces are forces which have a common line of action, i.e. the line of action of the forces lie along a single straight line.

Examples:

1. Two people standing at the opposite ends of a rope and pulling on it.


2. A Suspended load by a cable


3. If two people push a box standing adjacent to each other and both pushing in the same direction, then it is collinear as they can not intersect each other.

Co-Planar Forces:

When, the line of action of the forces lie in the same plane, the forces are called Coplaner.

Examples:

1. When a boy skates down a hill, two forces act on it in the same plane.
   Force A: Weight of the boy acting downward
   Force B: Force of acceleration acting along the hill on some angle.


2. When someone rides in a RollerCoaster and rollercoaster reaches some height then three forces act on the rollercoaster in same plane.
   Force A: Force of weight acting downward.
   Force B: Normal reaction of rollercoaster which is in opposite diirection of weight.
   Force C: Acceleration of the rollercoaster at some angle.


3. When a weight a pushed upwards on a slope three forces act on it in the same plane.
   Force A: Weight of the box acting downward
   Force B: Normal reaction of the box acting upward.
   Force C: Force which pushes the box at an angle on the slope.

Concurrent Forces:

Concurrent forces means a system of force whose line of action meets at one same point.

Examples:

1. When a barge is pulled by two tug boats using ropes tied on a same point on the barge, two concurrent forces along the ropes are pulling the barge.


2. Suspension cable with a common end having weights suspended on it.


3. If many people stand the ends of a rope and pull on it in a tug of war, the forces are concurrent because the effect of the forces will intersect at the same point (presumably in the middle of the rope).

Non-Concurrent and Co-Planar Forces:

Nonconcurrent and coplanar forces are two or more forces whose magnitudes are equal but act in opposite directions with a common line of action in the same plane.

Examples:

1. When driving a car your hands are opposite to each other on the steering wheel. The forces you apply with both hands when turning, one hand pushes while the other pulls the steering wheel.


2. When a cyclist pedals, his or her feet are parallel. One foot pushes a petal forward while the other pushes the other pedal backward. These two forces cause the wheels on the cycle to rotate.


3. When two people sit on the opposite sides of a seesaw and swing it upward or downward by pushing the ground alternatively they form a system of two non-concurrent and coplanar forces.

Concurrent and Co-Planar Forces:

Concurrent and coplanar forces means the line of the action of the forces meets with each other at one same point and lies the same plane.

Example:

1. When a car is driven on a road in real life the force of friction and force of acceleration of the car acts on the car means they have a same point which is car and they lie in the same plane.


2. When a load is suspended load by one or more cables, the gravity which acts downward and the cables which act upward have a same concurrent point i.e load, and they lie in same XY plane.


3. The ceiling fan is acted upon by force of gravity downward the force of tension which keeps it upward, both of these force acting in the same plane acts on the ceiling fan which means they are concurrent and coplanar.