Question

For problems that involve an object accelerating along an inclined plane, how can the weight be used to determine the force component that causes motion?

The weight is the full force that acts perpendicular to the surface of the ramp.
The weight times the cosine of the ramp’s angle is the force perpendicular to the ramp.
The weight times the sine of the angle of the ramp acts down along the ramp.
The weight times the cosine of the angle of the ramp acts down along the ramp.

Answer 1

Correct answers: 2 and 3.

Explanation: weight mg acts vertically downward. Resolving it into components relative to the plane (θ = angle of the ramp above horizontal):
- component perpendicular to the plane (normal): mg cosθ,
- component parallel to the plane (causing motion down the ramp): mg sinθ.

(Option 1 is wrong because weight is vertical, not always perpendicular; option 4 is wrong because the down‑slope component is mg sinθ, not mg cosθ.)