That s not right there s no sign difference You have R X F Newton is a scalar factor within F and meter is a scalar factor within R The scalar factors commute even though the underlying vectors do not Example 2 0 0 X 0 3 0 0 0 2 3 0 0 3 2 Likewise 1 m 0 0 X 0 1N 0 0 0 1 m N 0 0 1 N m