Mechanics and Materials Flashcards
What is Newton’s first law?
If no resultant force acts on an object, it’s motion will be constant (velocity will not change).
What is Newton’s second law?
F = ma
What is Newton’s third law?
For every action (force), there is an equal and opposite reaction (force) (not balanced forced). This is why total momentum is conserved.
What is inertia?
The tendency for an object’s motion to stay constant if no F.
What is the principle of moments?
Sum of total clockwise moments = sum of anticlockwise moments.
When is an object in equilibrium?
Translation equilibrium (no resultant force)
Rotational equilibrium (no resultant moment)
What is a couple?
Two equal and opposite forces that cause a resultant moment but no resultant force.
How do 2 springs behave in series and parallel?
Series: k is halved, springs extend more
Parallel: k is doubled, springs extend less
What does the area between the loading and unloading curve tell you?
Energy lost as heat during loading and unloading.
How does the Young Modulus graph of a brittle and ductile material differ?
Ductile: large plastic region (can be drawn into long wires)
Brittle: high E, no plastic region as it will snap beyond limit of proportionality
Which way does tension act?
Opposite to the applied force.
