Let’s solve this step by step.
We are told:
- The
load (the weight being lifted) is
150 N.
- The
effort (the force you need to pull with) is
25 N.
- We’re also told that
6 pulleys are required, and we can see from the diagram that there are 6 rope segments supporting the load — which matches the number of pulleys in a block-and-tackle system like this.
In a pulley system, the
mechanical advantage (MA) tells us how much the system multiplies your effort. It’s calculated as:
>
Mechanical Advantage = Load ÷ Effort
So let’s plug in the numbers:
> MA = 150 N ÷ 25 N =
6
That means the pulley system gives you a mechanical advantage of 6 — so you only need to apply 1/6th of the load’s weight to lift it.
Now, in an ideal pulley system (no friction), the mechanical advantage equals the number of rope segments pulling up on the moving part (or the number of strands supporting the load). In this case, since MA = 6, we need
6 rope segments sharing the load — which usually means
6 pulleys arranged properly (as shown in the diagram).
Also, notice:
Effort × Number of ropes = Load
→ 25 N × 6 = 150 N →
✔ Checks out!
So everything matches:
- With 6 pulleys (and thus 6 supporting rope segments),
- You apply 25 N of effort,
- And you can lift a 150 N load.
Final Answer:
6
Parent Tip: Review the logic above to help your child master the concept of mechanical advantage of a pulley worksheet.
