Physics Circle home Student Login

Home›Chapters›Work, Energy and Power PYQs›Work by a Constant Force›Question 15

JEE Main 2021 (22 Jul, Shift 2) · Work by a Constant Force

Work by a Constant Force question from JEE Main 2021 (22 Jul, Shift 2)

Q15JEE Main 2021 · 22 JUL · SHIFT 2Easy

Work by a Constant Force

A porter lifts a heavy suitcase of mass 80 kg and at the destination lowers it down by a distance of 80 cm with a constant velocity. Calculate the work done by the porter in lowering the suitcase. (take g = 9.8 ms−2{}^{-2})

Show answer and solution

Answer: (c)

  1. Constant velocity, so the porter's upward force F=mgF = mg.
  2. Displacement is downward, so the angle is 180∘180^\circ: W=−mghW = -mgh.
  3. W=−80×9.8×0.8=−627.2W = -80 \times 9.8 \times 0.8 = -627.2 J
  4. So the answer is (c) −627.2-627.2 J.
Report a mistake

More questions on Work by a Constant Force