For a particle of mass 1 kg, r⃗=(î+2ĵ−3k̂) m and v⃗=(2î−2ĵ+3k̂) m/s. If angular momentum magnitude is √(13x) kg·m²/s, find x.
Physics · Mixed Chapter
JEE Main Practice

Question

For a particle of mass 1 kg, r⃗=(î+2ĵ−3k̂) m and v⃗=(2î−2ĵ+3k̂) m/s. If angular momentum magnitude is √(13x) kg·m²/s, find x.

G1 Physics · Accepted Answer

Step 1: Angular momentum L⃗=r⃗×(mv⃗), with m=1 kg. Step 2: Cross product r⃗×v⃗=(0î−9ĵ−6k̂), so |L⃗|²=0²+9²+6²=117. Step 3: √(13x)=√117 ⇒13x=117 ⇒x=9.