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JAMB Physics 1986 Question 15

Question 15

Newton's Laws and Momentum

A 1000 kg elevator is descending vertically with an acceleration of 1.0 m s−2. If the acceleration due to gravity is 10.0 m s−2, the tension in the suspending cable is

  1. A.1.0 N
  2. B.10.0 N
  3. C.9000.0 N
  4. D.11 000.0 N
Show the answer and explanation

Answer: C (9000.0 N)

Explanation

Accelerating downwards, mg − T = ma, so T = m(g − a) = 1000 × 9 = 9000 N.