Question
Physics Question on Motion in a plane
The value of P so that the vectors 2i^−j^+k^,i^+2j^−3k^ and 3i^+Pj^+5k^ are coplanar should be
A
16
B
-4
C
4
D
-8
Answer
-4
Explanation
Solution
For coplanarity 35mm2 1 3 −12P1−35=0 or 2(10+3P)+1(5+9)+1(P−6)=0 or 20+6P+5+9+P−6=0 or 7P+34−6=0 or 7P+28=0 or 7P=−28 ⇒P=−728=−4