Mechanics

Name	Definition	Formulae
STATIC
Centre of mass	The point from which all the mass of the object appears to act
Centre of gravity	The point from which all the weight of the object appears to act
KINEMATICS
Suvat equations	$s=ut+frac{1}{2}at^{2}$ $v^{2}=u^{2}+2as$ $s=frac{(u+v)t}{2}$
NEWTON’S LAWS
Newton’s First Law	An object will remain at rest, or in a state of uniform motion in a straight line, unless acted upon by a resultant force
Newton’s Second Law	The resultant force is directly proportional to the rate of change of momentum and in the same direction of the momentum
Newton’s Third Law	To every action, there’s an equal and opposite reaction Act on different bodies Opposite direction Same magnitude Same kind
MOMENT
Moments	The force multiplied by the perpendicular distance from the pivot to the line of action of the force	Unit: Nm
Law of moments	For any object in equilibrium the sum of the clockwise moments about any point is equal to the sum of the anticlockwise moment about the same point
WORK DONE, ENERGY & POWER
Work Done	The product of: F (magnitude of the force) S (magnitude of displacement s of point of application of force) is the angle between the force and displacement vector)	Unit:
Energy	The property of object that gives it the ability to do work
Kinetic energy	The work done to accelerate an object of mass m, from rest to a speed v $Delta E_{k}=E_{k}^{'}-E_{k}=W_{D}$	$E_{k}=frac{1}{2}mv^{2}$ $=frac{p^{2}}{2m}$
Potential energy	The ability of an object to do work by virtue of its position or state
Gravitational potential energy	The energy an object has due to its position in a gravitational field	$E_{p}=mgh$
Power	The rate of doing work with respect to time Unit: $W=frac{J}{s}$ 1 watt is 1 J of E transferred in 1 sec	$P=frac{Delta W}{Delta t}$
Efficiency	$eff=frac{Useful E output}{Total E input}$