Every body continues at a state of rest or of uniform (unaccelerated) motion unless acted on by an external force
2nd Law
The acceleration of a body is directly proportional to the external
force acting on the body and take place in the direction of the force
F=ma
The Newton (N) is defined as the force to accelerate a mass of 1kg at 1m/s^2
3rd Law
If A exerts a force on B, then B exerts and equal and opposite force on A
D-T Graphs
Gradient=velocity
V-T Graphs
Gradient = Acceleration
Area under graph = distance
Conservation of momentum
The total linear momentum of a system of interacting (colliding)
bodies, on which no external force is acting, remains constant
If two bodies A and B collide they exert qual and opposite forces on each other
(Newton's 3rd Law), and by Newton's 2nd Law each body experiences the same
acceleration. As the changes are oppositely directed the total change in momentum is 0
Elastic Collision
No loss of kinetic energy
Free Fall
Galileo
Dropped balls from the Leaning Tower of Piza to see acceleration during free fall
He discovered that objects fall at the same speed regardless of their mass
Aristotle
Aristotle assumed that heavier objects would fall faster than lighter ones
Weight = mass x acceleration in free fall (g)
W = mg
Torque (Moments)
M = Fd
M = Moment, F = magnitude of Force, d = perpendicular distance
Total clockwise moment = Total anticlockwise moment (in equilibrium)
Equilibrium, Centre of Mass and COG
Pressure = force / area
Work, Energy and Power
W=Fd
Work done = force x distance moved
Kinetic energy = ½mv^2
GPE = mgh
Therefore, Increase/decrease in GPE = mg(change in h)
Power = energy/time
Power is the rate of doing work in Watts
A pendulum converts GPE into KE and back to GPE,
until it stops as it loses energy in other forms (e.g. heat)