Connected Bodies: Tension, Pulleys and Lifts · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Bodies joined by a rope

Science · Forces & Motion · ages 16-18
Name ______________________   Date ____________

  1. What is true of the tension in one light string?

    • It is the same along the string
    • It is bigger near the heavier mass
    • It is always zero

  2. What is the first step with two bodies joined by a rope?

    • Write one equation mixing both masses at once
    • Draw one free body diagram per body
    • Guess the tension and check it later

  3. Why do connected bodies share the same size of acceleration?

    • Because the string stretches to suit each mass
    • Because pulleys add extra force
    • Because both move as one unit along the string

  4. For that same pulley pair, what is the rope tension in N?

    Answer: ______________

  5. Masses of 3 kg and 1 kg hang over a light pulley. Take g as 9.8. What is their acceleration in metres per second squared?

    Answer: ______________

  6. A person stands on a scale in a lift that starts moving up. What does the scale do?

    • Reads more than when standing still
    • Reads the same as when standing still
    • Reads less than when standing still

  7. Tom writes a single F is m a equation mixing both masses and one tension, then solves once. Is Tom right?

    • Yes, one equation is always enough
    • No, tension pulls differently on each body
    • No, write F is m a per body, then solve

  8. A 60 kg person stands on a scale in a lift accelerating up at 2 metres per second squared. Take g as 9.8. What does the scale read in N?

    Answer: ______________

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Answer key

For grown-ups. Fold this page away before handing over the rest.

Bodies joined by a rope W1-mt_qk2gn4tUoN-s1

  1. It is the same along the string · One light string carries one pull all along its length.
  2. Draw one free body diagram per body · Each body gets its own diagram and its own equation before anything is combined.
  3. Because both move as one unit along the string · Joined motion means one shared rate of speeding up along the string.
  4. 14.7 · For the 1 kg mass, T minus 9.8 is 4.9, so T is 14.7.
  5. 4.9 · Net pull 2 g over total mass 4 gives 19.6 over 4, which is 4.9.
  6. Reads more than when standing still · Upward acceleration needs an extra upward push, so apparent weight rises.
  7. No, write F is m a per body, then solve · Each body needs its own equation; adding the pair removes tension cleanly.
  8. 708 · The floor pushes 60 times 9.8 plus 2, which is 60 times 11.8.
Worksheet · LightMySky