# angular momentum using unit-vector notation

**1. The problem statement, all variables and given/known data**

At one instant, force F: 4.0j N acts on a 0.25 kg object that has position^vector^V : (2.0t – 2.0k) m and velocity vector /: (-5.0i + 5.0k) m/s. About the origin and in unit- vector notation, what are (a) the object’s angular momentum and (b)the torque acting on the object

m = .25kg

f = (4.0 N)j

v = (-5i + 5k)

**2. Relevant equations**

Torque = (Yz-Zy)+(Zx-Xz)+(Xy-Yx)

KE= 1/2mv^2 + 1/2lw^2

**3. The attempt at a solution**

A) not quite sure where to start with A

B) (2i + 4j -2k)*(-5i + 4j +5k)

((4*-2)-(5*4)) – ((-2*5)-(-5*-4))-((2*4)-(4*2))

http://ift.tt/1nWHge0

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