Question

Under what conditions is the work done i) maximum and ii) minimum?

• A. i) When force and displacement are parallel to each other and ii) When force and displacement are at 180⁰ to each other.
• B. i) When force and displacement are parallel to each other and ii) When force and displacement are at perpendicular to each other.
• C. i) When force and displacement are perpendicular to each other and ii) When force and displacement are parallel to each other.
• D. i) When force and displacement are at 180⁰ to each other and ii) When force and displacement are parallel to each other.
• E. i) When force and displacement are at 45⁰ to each other and ii) When force and displacement are perpendicular to each other.

Answer 1

The correct option is B

i) When force and displacement are parallel to each other and ii) When force and displacement are at perpendicular to each other.

i) Work done is maximum when Force & Displacement are in the same direction as θ = 0, implying W = FS Cos(0) = FS

ii) Work done is minimum when the Force & Displacement are perpendicular to each other.

W = FSCosθ = FSCos90 = FS(0) = Zero