Kushagra Madhukar
Last Activity: 4 Years ago
Hello student
By law of vector addition, the resultant vector can be given as
R = P + Q
Now when Q is doubled the new resultant vector can be given as
R’ = P + 2Q
since, R’ is perpendicular to P
hence there dot product should be zero
or, R’ . P = 0
or, ( P + 2Q ).P = |P|2 + 2Q.P = 0
or, 2P.Q = -|P|2
Now, |R|2 = |P|2 + |Q|2 + 2P.Q
= |P|2 + |Q|2 – |P|2
= |Q|2
or, R = Q
Hope it helps
Regards
Kushagra