Dynamics
Newton's First Law
An object at rest stays at rest...
Translational Equilibrium
Free body diagram
Newton's Second Law
F = ma
Mass
Weight
Scalar
Kilogramme (kg)
Quantity of Matter
Inertia
Force of gravity on the object
Vector
Newtons (N)
F = (∆mv)/∆t = ∆p/∆t
Newton's Third Law
Every action has an equal and opposite reaction
True for both contact & non-contact forces
Motion with resistive forces
Drag
Motion under gravity with air resistance
Friction
Horizontal motion with air resistance
Projectile motion with air resistance
Materials in contact
Magnitude of contact force
Speed
Area presented
Streamlined
Terminal velocity
Area & Velocity
Higher speed Higher resistance
With air resistance, projectile path not symmetrical
Reduces both height & range
Not mass
Momentum
p = mv
Vector
kgm/s
Conversion of Moment
Initial = final (no external forces)
Initial parallel to = final parallel to
Kinetic energy
E_k = 1/2(mv^2)
Explosions
Seperation
Always inelastic
Elastic interaction (conserved)
Inelastic interaction (not conserved)
Relative speed
Two Same direction
One moving only
Two Opposite direction
The numerical value is always positive
relative speed of approach = relative speed of separation (for perfectly elastic collisions)
V_A + V_B
V_A - V_B
V_A