Mechanics and materials Flashcards
What is a scalar quantity?
A quantity with only magnitude
What is a vector quantity?
A quantity with magnitude and direction
What is the principle of moments?
The principle of moments states that for an object in equilibrium, the sum of anticlockwise moments about a pivot is equal to the sum of clockwise moments.
What is newtons 1st law?
An object will remain at rest or travelling at a constant velocity until it experiences a resultant force
What is Newtons 2nd law?
The acceleration of an object is proportional to the resultant force experienced by the object F=ma
What is newtons 3rd law?
For each force experienced by an object, an object exerts an equal and opposite reaction force.
What are the two types of collisions?
Elastic and inelastic
What is conserved in elastic collisions?
In elastic collisions momentum and kinetic energy are conserved
What is conserved in inelastic collisions?
In inelastic collisions only momentum is conserved.
What is the definition of work done?
The force causing a motion multiplied by the distance travelled in the direction of the force.
What is the conservation of energy?
Energy cannot be created or destroyed only transferred from one form to another.
What is Hooke’s law?
Extension is directly proportional to the force applied given the environmental conditions are kept constant.
What is the limit of proportionality?
The point at which Hookes law is no longer obeyed.
What is the elastic limit?
if you increase the force applied beyond this the material will no longer return to its original position
What is tensile stress?
The force applied per unit of cross sectional area
