physics eq's 2 Flashcards
The formula for: average velocity?
v = displacement / time
The formula for: average acceleration?
a = velocity / time
The formula for: uniform accelerated motion –> solved for d (3)
d = 1/2 (Vo + V)t missing a d = Vot + 1/2at^2 missing V d = Vt - 1/2at^2 missing Vo
notice the difference in +/-
The formula for: solved for final velocity (2)
V^2 = Vo^2 + 2ad missing t V = Vo + at missing d
the area under a velocity vs. time graph gives?
displacement
newtons second law
Fnet = ma
if an object has constant velocity what is true of Fnet?
no acceleration (constant v) so Fnet = 0 (i.e. dynamic equilibrium)
formula for: weight?
w = mg (g is 10 unless on different planet)
formula for: gravitational pull between two objects
Fg = G x Mm / r^2
formula for g (force of gravity)?
we can combine w = mg with Fg = G x Mm / r^2
(note w = Fg)
we get: g = G x M/r^2
formula for static and kinetic friction
Fk = Fn x μk
Fsmax = Fn x μs
μs > uk always
what is the equation for the parallel force of gravity on an object sitting on an inclined plane?
sin slides down the slope
mgsinθ
the formula for: the centre of mass for a multi-mass object
Xcm = m1x1 + m2x2 +m3x3 / m1 + m2 + m3
x is the distance from a set point
the formula for: centripetal acceleration
a = V^2 / r
if r increases what happens to centripetal a?
it actually increases since r is proportional with v and v is squared in a = V^2 / r
the formula for: centripetal force
Fc = m x V^2 / r
formula for: torque (2)
T = F x d x sinθ
or
T = F x L L = lever arm
what decreases rotational inertia?
making the mass closer to the axis of rotation
the formula for? work?
W = F x d x cosθ
measured in joules
note: this opposes torque which is
T = F x r x sinθ
measured in Nm
the formula for? power?
P = W / t
P = F x v
if force is parallel to velocity
the formula for? kinetic energy and gravitational potential energy
KE = 1/2mv^2
PEgrav = mgh
t or f, ΔKE = total Work
true - work energy theorem
the formula for? conservation of mechanical energy
KE1 + PE1 = KE2 + PE2
in friction is involved
KE1 + PE1 + Work = KE2 + PE2
Work = Ff x d
the formula for? mechanical advantage
F needed without machine / F needed with machine