Hi. I think this is my 1st post here but I browse a lot on the forum(adsbygoogle = window.adsbygoogle || []).push({});

I was trying to know the velocity at a point on a rigid Body (in 2D) and i found this equation on a paper:

http://members.fortunecity.de/porquilho/eqVel.jpg

where:

Vap = velocity at point P (body A)

Va1 = Linear Velocity of the Rigid Body CM (m/s)

w1 = Angular Velocity of the Rigid Body (rad/s)

rap with a invers "T" = the perpendicular distance vector from the CM to point p.

Im working on 2 dimension here so angular velocity is just a scalar

The question i have is the unreal result that this equation gives to me, for exemple:

Va1(0, -5)

w1=1.5;

rap(-5,-20) -> now we take the prependicular vector (90Âº to the left)

rapT(20, -5);

and if im not mistak making the calculations

Vap = (0,-5) + ( 1.5*20 + 1.5*(-5))

Vap = (0,-5) + ( 30+(-7.5))

Vap = (0,-5) + 22.5 = (22.5, 17.5);

Vap=(22.5, 17.5)

I think this value is too high, are my calculations wrongs ?

HELP ME

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Velocity at P

**Physics Forums | Science Articles, Homework Help, Discussion**