The resultant of F⃗₁ = pî+3ĵ−k̂, F⃗₂ = −5î+ĵ+2k̂, and F⃗₃ = 6î−k̂ has magnitude 5 units. Find p.
Physics · Mixed Chapter
JEE Main Practice

Question

The resultant of F⃗₁ = pî+3ĵ−k̂, F⃗₂ = −5î+ĵ+2k̂, and F⃗₃ = 6î−k̂ has magnitude 5 units. Find p.

G1 Physics · Accepted Answer

Step 1: Resultant = (p−5+6)î + (3+1)ĵ + (−1+2−1)k̂ = (p+1)î+4ĵ. Step 2: |R⃗|²=(p+1)²+16=25, so (p+1)²=9. Step 3: p+1=±3 gives p = 2 or p = −4. The source key is p = 2, but no sign restriction is provided, so both satisfy the magnitude condition.