BeginnerTopic 1 of 106Engineering Mechanics
Force
A push or pull that can change motion or shape; measured in newtons and treated as a vector.
In depth
A force is a vector interaction that accelerates a mass or deforms a body. It is characterised by magnitude, direction and point of application, and is measured in newtons (1 N = 1 kg·m/s²). Forces are contact (friction, tension, normal) or body forces (gravity, magnetic).
Key points
- Forces add as vectors
- Line of action matters for rigid bodies
- Net force determines acceleration
ExampleGravity on a 70 kg person is about 686 N downward.
Every structure, machine and vehicle is designed by predicting how forces push and pull on it, so force is the starting quantity of mechanics.
What is Force?
A push or pull that can change motion or shape; measured in newtons and treated as a vector.
Why is it important to understand force?
Every structure, machine and vehicle is designed by predicting how forces push and pull on it, so force is the starting quantity of mechanics.
Is a force a scalar or a vector?
A force is a vector, so it needs both magnitude and direction. Two forces of equal size pointing in opposite directions cancel, but the same size at right angles do not.
What units are used for force?
The newton in SI units, where one newton accelerates one kilogram by one metre per second squared. Imperial work often uses pound-force.
How is Force used in practice?
Typical applications include estimating the wind load on a sign board, sizing the cable that holds a lift car and calculating the thrust needed to accelerate a trolley.
What should I learn before Force?
It is the first topic in Engineering Mechanics, so no earlier topic in this course is required.
What are the key points of Force?
Forces add as vectors. Line of action matters for rigid bodies. Net force determines acceleration.
Can you give an example of Force?
Gravity on a 70 kg person is about 686 N downward.
What comes after Force?
The next topic is "Newton's laws", which builds directly on this one.
How difficult is Force?
It is classed as Beginner in Engineering Mechanics (topic 1 of 106). It is an entry-level topic. It relies only on basic school mathematics and the ideas introduced earlier in this discipline.