A force acts at a point whose position vector from the origin lies in the – plane (so )

PHYSICS · Single correct · AP · Physics 1: Algebra-based · Torque and Rotational Dynamics · Torque and Rotational Dynamics

Problem

A force

\mathbf{F}=10\,\mathbf{j}\,\text{N}

acts at a point whose position vector from the origin lies in the

x

–

z

plane (so

y=0

). If the required torque about the origin is

\boldsymbol{\tau}=20\,\mathbf{k}\,\text{N m}

, which one of the following position vectors (in metres) satisfies the condition? (a)

0\,\mathbf{i}+0\,\mathbf{j}+2\,\mathbf{k}

(b)

2\,\mathbf{i}+0\,\mathbf{j}+0\,\mathbf{k}

(c)

-2\,\mathbf{i}+0\,\mathbf{j}+0\,\mathbf{k}

(d)

1\,\mathbf{i}+0\,\mathbf{j}+0\,\mathbf{k}