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3 marksThermal Measurements

CSEC Physics · 1989 · Paper 2 · Question 3(b)(ii)

A car and occupants have a mass of 900 kg, travelling at 90 km h^-1 (25 m s^-1). When it stops suddenly, kinetic energy is converted to internal energy in iron brake drums.

Each of the four brake drums has a mass of 2.5 kg. Find the rise in temperature which occurs when the car is brought to rest. [Specific heat capacity of iron = 450 J kg^-1 K^-1.]

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Other parts of this question

  1. 3(a)Write 'YES' or 'NO' in EACH of the boxes below to show whether each system possesses the energy indicated at the top of the column.[4 marks]
  2. 3(b)(i)Calculate the kinetic energy of the moving car.[2 marks]
  3. 3(c)(i)With reference to Newton's laws of motion explain why this might happen.[3 marks]
  4. 3(c)(ii)With reference to Newton's laws of motion explain how the wearing of a seat-belt helps to prevent such an accident.[2 marks]
  5. 3(d)A car, carrying a passenger, stops suddenly. Describe the energy changes which take place as the passenger is brought to rest by his seat-belt.[2 marks]

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