Number of degrees of freedom of two particles connected by a rigid rod moving freely in a plane is?

Question

Hi respected researchers and scholars,

I have a question regading degrees of freedom

Number of degrees of freedom of two particles connected by a rigid rod moving freely in a plane is _______ ?

I have in my mind is: For a single particle it is 2 in a plane,

Q. 1 What if two or three independent particles in a plane? Is it 4

Q. 2 if two particles connected by a rigid rod moving freely in a plane ?

Need your kind attention. Thanks

score 2 · Answer 1 · answered Aug 09 '20 at 03:55

2

Three real parameters, 2 for center of mass of whole thing, one for rotation angle would do it. Don't know if that's what you mean by degree of freedom...

answered Aug 09 '20 at 03:55

coffeemath

7,403

is it right to say one for x-axis, one for y axis and one for rotation? – Taj Aug 09 '20 at 04:09
@Taj Yes, since $x,y$ would specify center of mass. – coffeemath Aug 09 '20 at 04:20

score 1 · Answer 2 · answered Aug 09 '20 at 04:14

Think of DOF as the number of parameters to completely define the position of the particles

You need two parameter for the first particle, the $x$ and $y$ coordinate.

After specifying the position of the first particle, then specify the angle of the rigid rod.

Thus 3 DOF in total

Number of degrees of freedom of two particles connected by a rigid rod moving freely in a plane is?

2 Answers2