In a block and tackle system with 6 pulleys in each of two blocks, if a force of 260 N is required to lift a load of 300 kg, what is the efficiency of the system?

To determine the efficiency of a block and tackle system, the formula to use is:

[ \text{Efficiency} = \left( \frac{\text{Mechanical Advantage}}{\text{Velocity Ratio}} \right) \times 100% ]

The mechanical advantage (MA) is the ratio of the load lifted to the effort applied. Here, the load is 300 kg, which translates to a weight of:

[ \text{Load} = 300 , \text{kg} \times 9.81 , \text{m/s}^2 = 2943 , \text{N} ]

The effort (force required) is given as 260 N. Therefore, the mechanical advantage of the system can be calculated as follows:

[ \text{MA} = \frac{\text{Load}}{\text{Effort}} = \frac{2943 , \text{N}}{260 , \text{N}} \approx 11.31 ]

Next, we find the velocity ratio (VR). In a system where there are 6 pulleys in each block, the total number of supporting sections of rope contributes to the velocity ratio. Specifically, the velocity