# Forces 3

The ‘how tough’ and ‘how strong’

Discipline
Materials

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With the discipline of Motion, we know exactly how stuff moves. But not why. Why does acceleration exist? What causes it? The answer is forces! Also called the topic of dynamics.

This discipline answers the simple yet all-embracing questions: ‘how tough’ and ‘how strong’.

3rd of 3 courses in the Forces discipline.
Meet the other participants in the Forces classroom.

New properties
Force $\vec F$
Mass $m$
Friction coefficients $\mu_k$, $\mu_s$
Stiffness / spring constant $k$

New phenomena
Pseudo-forces
Kinetic friction (Amontons' law) $f_k=\mu_k n$
Static friction $f_s\leq \mu_s n$
Weight $w=mg$
Normal force $\vec n$
Tension $\vec T$
Elastic force (Hooke's law) $F_\text{elastic}=k\Delta L$

New mechanisms
Newton's 1st law $$\sum\vec F=0$$
Newton's 2nd law $$\sum\vec F=m\vec a$$

Technical
Skill Content
Engineering
Skill Content
Mathematical
Technical
Skill Content
Historical
Ending

• 10 Skills