May work in the following CASIO models: fx-570ES, fx-570ES Plus, fx-115ES, fx-115ES Plus, fx-991ES, and fx-991ES Plus

Use VECTOR mode: [MODE] → 8:VECTOR

This mode is made primarily for vector quantities, thus, handling forces in 3D is straightforward.

Enter position vector:

[MODE] → 8:VECTOR → 1:VctA → 1:3

**r** = VctA = [ -4 6 -3 ]

Solve for vector **F**: AC

**F** = 500[×]([SHIFT] → [5 VECTOR] → 3:VctA ÷ [SHIFT] → [hyp Abs]( → [SHIFT] → [5 VECTOR] → 3:VctA) ) =

Calculator display: 500×(VctA÷Abs(VctA))

**F** = [ -256 384 -192 ] *answer*

Note: the unit vector λ is:

λ = [SHIFT] → [5 VECTOR] → 3:VctA ÷ [SHIFT] → [hyp Abs]( → [SHIFT] → [5 VECTOR] → 3:VctA)