vector A of magnitude 20 units lies in the direction 45 degrees S of E, while vector B, of magnitude 30 units is in the direction 60 degrees W of N. Calculate the scaler product A.B
"\\vec{A}*\\vec{B}=| \\vec{A}|| \\vec{B}|\\cos\\theta"
"\\theta_1= \\angle(W,S)+45^0\\text{(S of E)}+60^0\\text{(W of N)}="
"= 90^0+45^0+60^0= 195^0"
"\\theta_1>180^0\\text{ hence this is the outer angle}"
"\\theta_1= 360^0-\\theta= 165^0"
"\\vec{A}*\\vec{B}=| \\vec{A}|| \\vec{B}|\\cos\\theta=20*30*\\cos{165^0}\\approx-579.6"
Answer: -579.6 scaler product
Comments
Dear Praiz jazz, 90° is the angle between West and South
Why did we plus the angles with 90°
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