- #1
pwnage101
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i have a mechanics problem. i want to represent the motion of a swinging rod (given initial conditions) as a function of time, but instead i can only find it as a function of the angle.
this rod has uniform density and freely pivots at one end.
Q = angle from 0 counter-clockwise to the rod
L = length
M = mass
Fgrav = force due to gravity
I = integral(r^2 dm, 0,L)
= integral(r^2 M*dl/L, 0,l)
= (M*L^2)/3
Fgrav = Mg -> Mg*cos(Q) tangentially
torque = F*L/2 = I*a
a = (3g/2L)*cos(Q)
how am i able to convert this a(Q) into a(t) ? (that's rotational acceleration by the way)
unfortunately, the following website was of no help. it simply took the exact same steps to get the exact same result
http://www.myphysicslab.com/pendulum1.html
this is for a graphical physics simulation I'm about to finish writing in Java. now i just need the formula
this rod has uniform density and freely pivots at one end.
Q = angle from 0 counter-clockwise to the rod
L = length
M = mass
Fgrav = force due to gravity
I = integral(r^2 dm, 0,L)
= integral(r^2 M*dl/L, 0,l)
= (M*L^2)/3
Fgrav = Mg -> Mg*cos(Q) tangentially
torque = F*L/2 = I*a
a = (3g/2L)*cos(Q)
how am i able to convert this a(Q) into a(t) ? (that's rotational acceleration by the way)
unfortunately, the following website was of no help. it simply took the exact same steps to get the exact same result
http://www.myphysicslab.com/pendulum1.html
this is for a graphical physics simulation I'm about to finish writing in Java. now i just need the formula