Explain why work is done on a book when it is lifted vertically upwards onto a shelf, and state the energy transfer that takes place.

AQA GCSE Physics (8463) — 4.5.2 Work done and energy transfer · Explain · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

A student lifts a book from the floor and places it on a shelf above their head.

Model answer (4 marks)

A force is applied by the student’s hand in the upward direction, which is the same direction as the book’s motion. The book moves a vertical distance equal to the height of the shelf, so the force and displacement are along the same line of action. The work done by the student’s muscles transfers chemical energy into the book, increasing its gravitational potential energy.

Examiner tips

  • Use the word ‘force’ and specify its direction relative to motion
  • Show that displacement is along the line of action
  • Mention the source of energy (muscles) and the type of energy gained (gravitational potential)
  • Keep each point brief but complete

Common mistakes

  • Confusing work with force or energy, or omitting the direction of force
  • Failing to state that the energy transferred is chemical from muscles
  • Not recognising the increase in gravitational potential energy

Mark scheme (4 marks)

  1. A force is applied to the book (in the direction of motion / upwards)
  2. The book moves (a distance) in the direction of the force / along the line of action of the force
  3. Energy is transferred from the muscles (chemical energy store) to the book
  4. The book gains gravitational potential energy

Key terms in this question

energy transfer

Related

More Work done and energy transfer questions

▶ Try answering this question with AI marking (free) →