Mechanics and materials

What is a couple

A pair of opposite coplanar forces

what is meant by the centre of mass

The point through which all the mass of an object acts

Newtons 1st law

An object stays at constant velocity until a force acts on it

Newtons 2nd law

F=ma

Newtons 3rd law

Every action has an equal and opposite reaction force

Differemce between elastic and inelastic collisions

Elastic collisions have same KE before and after, where in inelastic there is KE lost in the collision

How to answer long answer mechanics

Refer to relevant equations and quantities and how they change over time/experiments and state what it means

Elastic deformation vs plastic deformation

Elastic means the objects return to their normal shape, Plastic won’t

What is breaking stress (maximum tensile stress)

The minimum stress required to break a material

What is meant by brittle

Doesn’t deform plastically but breaks at a certain value

What is elastic limit

The force which the material will then by plastically deformed

What is the limit of proportionality

The point at which hookes law is no longer obeyed

What is the meaning of ductile

Can undergo a large amount of plastic deformation before fracture

How to calculate effective spring constant

In parallel, the sum of the spring constants

In series, the reciprocal of the sum of the reciprocols