Test Index

WAEC Physics 2013 Paper

Question : 43

Total: 46

Solution:

Concept:

Resultant of perpendicular forces is found using the parallelogram law and Pythagoras' theorem.

Explanation:

Resolve the forces into two perpendicular directions.

Choose upward and rightward as positive.

Vertical forces are

10\mathrm{N}

upward and

6\mathrm{N}

downward.

Vertical resultant

= 10 - 6 = 4\mathrm{N}

Horizontal forces are

20\mathrm{N}

rightward and

17\mathrm{N}

leftward.

Horizontal resultant

= 20 - 17 = 3\mathrm{N}

These two components are perpendicular, so the resultant force is:

R = \sqrt{(3)^2 + (4)^2} = \sqrt{9 + 16} = \sqrt{25} = 5\mathrm{N}

Answer:

5.0\mathrm{N}

Go to Question:

Prev Question

Next Question