Every Tuesday I post a common question you might encounter during your aptitude test. This week we will be covering a pulley example.

For more questions, have a look at the Firefighter Practice Tests – Premium Pack. They offer over 99 practice tests and over 1500 questions.

The Problem:

In the figure below, you have a pulley-system to lift a weight. What is the minimum value of force required to lift the 10 kg block?

  • 10 kg
  • 5 kg
  • 15 kg
  • 20 kg

pulley11 Aptitude Test Tuesday – Pulleys

The Solution:

With a suspended pulley, the upward forces in the two ropes are equal. Therefore each supports half of the load.

Half load of the 10 kg block = 5 kg.

The tension in the upper rope is half of the block’s weight.

Therefore the required force F is 5 kg.

pulley1a1 Aptitude Test Tuesday – Pulleys

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