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## Homework Statement

The position of a particle of mass m = 2.0kg is given at time t by the equation,

**r**= 3t

**i**- t

^{2}

**j**+ 2

**k**, where

**r**is measured in meters from the origin, and t is in seconds. What is the angular momentum of the particle with respect to the origin at time t = 2 s?

## Homework Equations

L = Iω = (mr

^{2})(ω)

## The Attempt at a Solution

I kind of understand the general idea of the problem, I think it's just the presence of i, j, k that is confusing me.

From the radius equation, I took the derivative to get the angular velocity equation.

ω = 3 i - 2t j

From there, I calculated r(2) and ω(2).

r(2) = 6i - 4j + 2k

ω(2) = 3i - 4j

Using the equation L = Iω = mr

^{2}ω

L = (2)(6i - 4j + 2k)

^{2}(3i - 4j)

Then, I just multiplied through to get the answer. But, the numbers look way too big and I'm not too sure I did it correctly.

Any help is appreciated!