Pushing force
Thrust
Pulling force
Tension
Resistive force
Friction
Rebound force
NCRF
Gravity modelling assumption
Vertical and CONSTANT
modelling assumption about surfaces
Smooth has NO FRICTION
Modelling assumptions about particles
Has negligible dimensions
Modelling assumptions about ‘light’ objects
0 mass
SUVAT without s
a = v-u /t
SUVAT without a
S = t (v+u)/2
SUVAT without u
S = vt - 1/2 at^2
SUVAT without v
S = ut + 1/2 at^2
SUVAT without t
V^2 = u^2 + 2as
displacement to velocity to acceleration
Differentiate
Acceleration to velocity to displacement
Integrate
r = (position vector)
r = r0 + s
s = displacement
r = original position
SUVAT not used in 2D
v^2 = u^2 + 2as because squares aren’t vectors
Modelling assumptions with projectiles
No air resistance,
Move freely under gravity,
No spin
time of flight =
2u sinθ / g
Horizontal displacement =
u^2 sin 2θ / g
Time reached maximum height = (in terms of time)
Time of flight / 2
Maximum height
u^2 sin^2 θ / 2g
NI definition
an object at rest will stay at rest and an object moving at a constant VELOCITY will remain at a constant velocity unless a RESULTANT force acts upon it
Rf =
F1 + F2 + F3 …
NII definition (maths)
The RESULTANT force acting on a body is EQUAL to the PRODUCT of the mass of the body and its acceleration and force and acceleration are in the same direction.
F = ma
NIII definition
The force exerted by body A on body B is equal in magnitude to the force exerted by body B on body A but in an opposite direction
Find tension between two bodies connected by a string
Equal magnitude and opposite directions from each box
THEREFORE can model 2 particles as ONE PARTICLE
equation for pulleys
NII and SUVAT
Direction of tension in pulley system
Always TOWARDS pulley and OPPOSES WEIGHT
