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physics

physics

by abhinav chandra -
Number of replies: 4

A uniform rod pivoted at its upper end hangs vertically. it is displaced through an angle of 60* and then released. find the magnitude of the force acting on a particle of mass dm at the tip of the rod when the rod makes an angle of 37* with the vertical

In reply to abhinav chandra

Re: physics

by aditya gopi -
using COE

Ui = Mgl(1-0.5xcos60)

Ki=0

Uf = Mgl(1-0.5xcos37)

Kf = 0.5 x ((Ml^2)/3) x w^2

you will get w^2 to be (9xg)/(10xl)

force in the tip of the rod

is dm x l x w^2

ans -> ((9 x (dm) x g)/10)


Please tell me if the answer is right.
In reply to aditya gopi

Re: physics

by aditya gopi -
sorry i forgot the translatory kinetic energy in the equation

Kf will thus have an additional factor of 0.5xMx(lw/2)square

thus w^2 comes out to be 18g/35l
In reply to aditya gopi

Re: physics

by abhinav chandra -
the actual answer is(0.9 dm g  2^0.5)
In reply to abhinav chandra

Re: physics

by aditya gopi -
Undetermined error: @@U_i = mg(l/2)(1-cos60)@@
Undetermined error: @@K_i=0@@

Undetermined error: @@U_f = mg(l/2)(1-cos37)@@

Undetermined error: @@K_f = (1/2)Iomega^2@@

u get
Undetermined error: @@omega^2 = (0.9g)/(l)@@

now the mass dm at the tip has forces

dm.g and centrifugal force of dm.l.Undetermined error: @@omega^2@@

angle between the forces is 37degrees
on calculating net force you get

1.803dmg


i do not know what is wrong.