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Question
A vector \[\vec{A}\] makes an angle of 20° and \[\vec{B}\] makes an angle of 110° with the X-axis. The magnitudes of these vectors are 3 m and 4 m respectively. Find the resultant.
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Solution
To find the resultant of two vectors `vecA and vecB`. we use the cosine law:
`R = sqrt(A^2 + B^2 + 2AB costheta)`
Where:
A = 3m, angle = 20°
B = 4m, angle = 110°
θ = angle between vectors A and B = 110∘ − 20∘ = 90∘
`R = sqrt(3^2 + 4^2 + 2 xx 3 xx 4 xx cos(90^\circ))`
`R = sqrt(9+16+0) = sqrt25`
= 5 m
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