Question

In unit-vector notation, what is the net torque about the origin on a flea located at coordinates (-2.0, 4.0 m, -1.0 m) when forces F1 = (-4.0 N) k and F2 = (-5.0 N) j act on the flea?

Answer 1

Answer:

Torque, $\tau=-21i-8j+10k$

Explanation:

Given that,

Coordinates, $r=(-2i+4j-k)\ m$

Force acting on the flea, $F=(0i-5j-4k)\ N$

Let $\tau$ is the net torque about the origin on a flea. It is given by the following formula :

$\tau=r\times F$

$\tau=(-2i+4j-k)\times (0i-5j-4k)$

$\tau=\begin{pmatrix}-21&-8&10\end{pmatrix}$

$\tau=-21i-8j+10k$

So, the net torque about the origin on a flea is $-21i-8j+10k$. Hence, this is the required solution.