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Given :

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Force F1 magnitude = 47 N

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Force F1 inclined angle θ1 =  18º  ( with positive X-axis in counter clockwise direction )

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Force F2 magnitude = 74 N

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Force F2 inclined angle θ2 =  280º   ( with positive X-axis in counter clockwise direction )

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θ2 =  360 - 280 = 80º   ( with positive X-axis in clockwise direction )

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Resultant Force magnitude F =?

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Resultant Force angle θ = ?

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\"\"

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From above figure

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Force F1 magnitude OA = BC = 47 N

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Force F2 magnitude OB = AC = 74 N

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Resultant Force magnitude F = OC

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Force F1 in X-Axis direction F1x = OA cos18

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F1x = 47 cos18

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F1x = 44.7

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Force F1 in Y-Axis direction F1y = OA sin18

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F1y = 47 sin18

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F1y = 14.52

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Force F2 in X-Axis direction F2x = OB cos(80)

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F2x = 74 cos(80)

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F2x = 12.8

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Force F2 in Y-Axis direction F2y = OB sin(80)

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F2y = 74 sin80

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F2y = 72.88

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F2y direction is downwards.So

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F2y = - 72.88

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Sum of all forces in X-Axis direction ΣFx = F1x+F2x

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ΣFx = 44.7+12.8

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ΣFx = 57.5

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Sum of all forces in Y-Axis direction ΣFy = F1y+F2y

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ΣFy = 14.52-72.88

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ΣFy = -58.36

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F = √ [( ΣFx )2+ ( ΣFy )2]

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F = √ [ 57.52 + (-58.36)2 ]

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F = √ [6712.1396]

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F = 81.93 N

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Resultant Force magnitude is 81.93 N

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Θ = tan-1( ΣFy / ΣFx )

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Θ = tan-1(-58.36/57.5)

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Θ = - 45.43o

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Negative symbol indicates clockwise direction (downwards) with positive X-axis.

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Resultant Force angle is 45.43º with positive X-axis in clockwise direction

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