Work equals force times displacement parallel to the force

Steps:

• Identify the displacement vector from start to end position of the block.
• Determine the component of displacement in the direction of force F, which is along the slope.
• Calculate work as F multiplied by this parallel displacement distance, denoted as r.
• Ignore perpendicular components, as they contribute zero to work by F.

Why A is correct:

• Work done by F is F times the displacement along F's direction (r), per the definition W = F · d = F d cos(0°) = F r.

Why the others are wrong:

• B uses p, likely a perpendicular or incorrect distance, ignoring the actual path along F.
• C adds q (possibly vertical rise) to p, overestimating by including non-parallel components.
• D adds r to p, double-counting the parallel displacement with an extra segment.

Final answer: A