Aptitude Test Tuesday – Pulleys
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
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.
