Question

simple machines - pulley system
a construction crew lifts approximately 560 lb of material several times during a day from a flatbed truck to a 32 ft rooftop. a block and tackle system with 50 lb of effort force is designed to lift it.

1. what is the required actual mechanical advantage?

formula substitute / solve final answer

1. how many supporting strands will be needed in the pulley system?

formula substitute / solve final answer

Explanation:

14.

Step1: Recall mechanical - advantage formula

The formula for actual mechanical advantage (AMA) is $AMA=\frac{Load}{Effort}$.

Step2: Substitute given values

Given load = 560 lb and effort = 50 lb. So, $AMA=\frac{560}{50}$.

Step3: Calculate the value

$AMA = 11.2$

Step1: Recall pulley - system formula

In a pulley system, the number of supporting strands (n) is related to the mechanical advantage. For an ideal pulley system, $n = AMA$ (since the ideal mechanical advantage of a pulley system is equal to the number of supporting strands).

Step2: Use the AMA value from previous question

We found $AMA = 11.2$. Since the number of strands must be a whole - number and we need to be able to lift the load, we round up to the next whole number.

Answer:

11.2

15.