
#1
Feb813, 03:43 AM

P: 4

What are the number of degrees of freedom of
1)a square sheet moving in XY plane 2)a triangular lamina moving freely in XY plane 



#2
Feb813, 01:26 PM

Mentor
P: 10,769

This looks like homework: What did you find out so far?




#3
Feb1013, 02:48 PM

P: 4

A square is composed of many particles with the constraint that distance between every particle is the fixed.so such a square is moving in XY plane.
if i consider two particles they have 41 =3degree of freedom(one is subtracted due to constraint that distance between particles are fixed).if i consider third particle it is defined by two coordinates and two constraints and therefore no degree of freedom.....the same for fourth fifth and so on..... so my answer is three and i dont find any difference in this respect with a triangular lamina...... I do not know the answer to the question.......please comment on this and say if you have any other opinion. 



#4
Feb1013, 03:38 PM

Mentor
P: 10,769

Degrees of freedom
Those 3 degrees of freedom just fix the current position of the square. What about its movement?




#5
Feb1013, 03:45 PM

P: 4

if i get generalized coordinates i can calculate coordinate velocities from it




#6
Feb1013, 03:46 PM

Mentor
P: 10,769

Is that related to the original question?
What do you mean with "get"? 



#7
Feb1013, 04:12 PM

P: 4

The question does not ask that .But i told a general principle.For example a simple pendulum which is oscillating in a plane.since its moving along the arc of a circle(distance from orgin is fixed) it has only one degree of freedom....theta.....which is the angle dat the string makes with vertical.......so if i know theta as a function of time.....i can differentiate "theta" to find generalised coordinate velocity



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