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## Homework Statement

A 2.4 kg particle-like object moves in a plane with velocity components

*v*x = 25 m/s and

*v*y = 80 m/s as it passes through the point with (

*x*,

*y*)coordinates of (3.0, −4.0) m. (Express your answers in vector form.)

(a) What is its angular momentum relative to the origin at this moment?

## Homework Equations

L=pxr

## The Attempt at a Solution

I did 2.4*the 3x3 matrix

i j k

25 80 0

3 -4 0

and this gave me 2.4*(-100-240)k = -816k.

[FONT=verdana, geneva, sans-serif]When I entered this in, I got this wrong, but without the minus sign (so 816k), the webassign accepted this as correct. However, this bothers me because isn't the correct sign supposed to be negative? [/FONT]