Mechanics and Materials Flashcards
Moment about a point
Force multiplied by the perpendicular distance from the line of action of the force to the point
Couple
- pair of coplanar forces
- equal in magnitude
- opposite directions
Principle of moments
For an object in equilibrium, sum of anticlockwise moments about a pivot is equal to the sum of clockwise moments
Acceleration time graphs
Area under is change in velocity
Velocity time graphs
- Gradient is acceleration
- Area under is displacement
Displacement time graphs
Gradient is velocity
SUVAT can only be used when…
there is uniform acceleration
Free Fall
when object experiences acceleration g
Friction
- force which opposes the motion of an object
- convert KE to other forms of energy
Terminal speed
Occurs when frictional forces are equal to driving forces
Newtons 1st Law
An object will remain at rest or at a constant velocity until it experiences a resultant force
Newtons 2nd Law
Acceleration of an object is directly proportional to resultant force
F = ma
Newtons 3rd Law
For each force experienced by an object, the object exerts an equal and opposite force.
Momentum
- Product of mass and velocity of an object
- Always conserved
Impulse
Change in momentum
Force-Time graph
Area is change in momentum
Elastic Collision
Both momentum and KE are conserved
Inelastic Collision
Only momentum is conserved, KE converted into other forms
Efficiency
Measure of how efficient a system transfers energy
Principle of conservation of energy
Energy cannot be created or destroyed
Density
Mass per unit volume
Hookes Law
Extension is directly proportional to the force applied given that environmental conditions are kept constant
