Question

Two vectors A and B are at right angles to each other, when​

Answer 1

answer : dot product of A and B equals zero. i.e., A.B = 0

explanation : if two vectors A and B are at right angle to each other. then dot product of A and B becomes zero.

it is because, dot product of A and B = |A||B|cosα , where α is angle between them.

we also know, cosine value at 90° becomes zero. when A and B are at right angle to each other , dot product of A and B , (A.B) = |A||B|cos90° = 0.

some important points :

• dot product is a scalar quantity.
• to find workdone, we use concept of dot product. you know as well, workdone is the dot product of force and displacement.i.e., W = F.S = |F|.|S|cosα