find the angle between vectors h=10i-11j+30k and p=-2i+12j-k

Question

it is physics question on the topic of vectors and scalars

Answer 1

Given vectors are h =10i-11j+30k

p = -2i+12j-k

Recall the formula

Angle between two vectors is Cos theta = a.b/|a||b|

h.p = 10(-2)-11(12)+30(-1)

= -20-132-30

= -182

|h| = sqrt(100+121+900) = sqrt(1121) = 33.48

|p| = sqrt(4+144+1) = sqrt(149) = 12.20

Cos theta = -182/(33.48)(12.20)

= -182/408.45

= 0.4455

theta = cos^-1(0.4455)

Comments

theta = cos^-1(-0.4455)

Angle between vectors h and p is 116.45^o