Question

When a boy pulls his sled with a rope, the rope makes an angle of 70° with the horizontal. If a pull of 20 pounds on the rope is needed to move the sled, what is the horizontal component force?

7 lb
19 lb
20 lb
24 lb

Answer 1

The answer to your question is 7 lbs.

Explanation:

Data

angle = 70°

force = 20 lb

horizontal component

Process

To solve this problem just imagine a right triangle, where the force is the hypotenuse and the horizontal component is the adjacent side.

1.- Look for a trigonometric function that relates the adjacent side and the hypotenuse.

cos Ф = adjacent side / hypotenuse

- Solve for the adjacent side

adjacent side = hypotenuse x cosФ

- Substitution

adjacent side = 20 x cos 70

- Simplification

adjacent side = 20 x 0.342

- Result

adjacent side = 6.84 ≈ 7 lb