Three coplanar forces of magnitudes $$$100 \mathrm{~N}, 50 \mathrm{~N}$$$ and $$$50 \mathrm{~N}$$$ act at a point $$$A$$$, as shown in the diagram. The value of $$$\cos \alpha$$$ is $$$\frac{4}{5}$$$. Find the magnitude of the resultant of the three forces and state its direction. ................................................................................................................................................................ ................................................................................................................................................................ ................................................................................................................................................................ ................................................................................................................................................................ ................................................................................................................................................................ ................................................................................................................................................................ ................................................................................................................................................................ ................................................................................................................................................................ ................................................................................................................................................................ ................................................................................................................................................................ ................................................................................................................................................................ ................................................................................................................................................................ ................................................................................................................................................................ ................................................................................................................................................................ ................................................................................................................................................................ ................................................................................................................................................................ ................................................................................................................................................................ ................................................................................................................................................................ ................................................................................................................................................................

Mathematics

IGCSE&ALevel

CAIE

Exam No：9709_s20_qp_41 Year：2020 Question No：1

Answer:

Resultant $=100-2 \times 50 \cos \alpha$
$20 \mathrm{~N}$
Direction is to the left (or equivalent)

Knowledge points:

4.1.2 understand the vector nature of force, and find and use components and resultants； Calculations are always required, not approximate solutions by scale drawing.

Answer:

Knowledge points:

Solution:

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