2.mechanics Flashcards
What is mechanics
How forces moves things
Newton’s first law
An object remains at rest or in uniform motion unless a resultant force acts on it
Newton’s second law
Resultant force is equal to the rate of change of momentum
F=ma
Newton’s third law
If object an exerts a force on object B, object B exerts a force on object A.
-forces are same type
-the forces the same size
-act in opposite directions
Details of free body force diagram (FBFD)
-show all forces acting on an object
-forces act from centre of the object
-arrows show the direction of the force
What is velocity
Rate of change of displacement
Velocity equation
Velocity =displacement/distance divided by time
Scalar
Magnitude only
Vector
Direction and magnitude
Acceleration equation
Acceleration = change in velocity / change in time
Magnitude is what
Resultants line
Direction is what
Angle
what does SUVAT stand for
S=displacement
U=initial velocity
V=final velocity
A=acceleration
T=time
Uniformly retarted
Decelerates at a constant rate
Free fall
Only gravity nothing else
A=g
Newtons 1st law
Object remains at rest or uniform motion unless a resultant force acts on it
Newtons 2nd law
Resultant force is equal to the rate of change of momentum
Newton third law
If object, a exerts, a force on object, B object, be exerts, a force an object
The forces are the same type
The forces are the same size
Act in opposite directions
 centre of gravity
Single point that you can consider that its whole weight to act through 
What is the gradient of a displacement time graph?
Velocity
Gradient of velocity graph
Acceleration
Centre of gravity
The point through which the weight of an object appears to act
Principle of moments
Will be in equilibrium if the sum of clockwise moments acting on it is equal to some of anticlockwise moments
Equilibrium in a body
Zero resultant force and zero resultant moment it will have zero acceleration
Conservation of energy
Energy cannot be created or destroyed only transferred
Work
The amount of work done meant the amount of energy transferred over moved in direction of the force
Power
Rate of energy transfer
Efficiency
Ratio of useful energy over total energy input
Momentum
Measure of an object motion
Conservation of linear momentum
Vector some of the memento of all objects in a system is the same before and after any interaction or collision between the objects
Explosion
Situation in which stationary object joined objects separate into component parts which move off a different velocities. The momentum must be conserved and explosions. 
