Compound Machines

What is a compound machine?

A compound machine is a machine composed of several simple machines.

Examples include bicycles and staplers.

Our Task

A group of 3, our team had to create a compound machine to lift a golf ball one foot up in the air using one little human input.

We started off by brainstorming 3 ideas and sketching and annotating them.

We decided on one of them and created an isometric sketch of it.

Unfortunately, we ran into problems when building this design and decided to utilize a different design.

This is what our finished product looked like:

Mechanical Advantage

The overall MA of our machine is 0.91. The second class lever had a MA of 1.192, the first class lever had a MA of 0.606, and the fixed pulley had a MA of 1.256.

Mechanical advantage dictates if a machine is useful. You would only use a machine if it makes your task easier, and the mechanical advantage is a good measure of the level of difficulty your task will be. This is why mechanical advantage is important, and should be considered when developing machines.

Conclusion

For which mechanism was it the easiest to determine the mechanical advantage or

drive ratio? Why was it the easiest?

The gear mechanism was the easiest because all we had to do was measure the diameter, and since the gears were the same they shared the same diameter, meaning a gear ratio of 1.

For which mechanism was it the most difficult to determine the mechanical

advantage or drive ratio? Why was it the most difficult?

The pulley was the most difficult to determine the mechanical advantage because we had to weigh the resistance and tape the cord to the vernier gauge to get the force value.

At what value would you estimate the input and output forces of your compound

machine? How did you arrive at your estimated values?

I estimated the input force to be .436 N and the output force to be .392 N. I used the mechanical advantage and the input force of the second class lever to estimate the values.

What modifications could you make to your compound machine to make it more

mechanically efficient?

I would increase the gear ratio by making one of the gears bigger to increase the gear ratio, and then increase the length on the first class lever to make it have a higher mechanical advantage.