Simple machines?

Question

I have questions and i need help I was absent when my class did this and no1 has the notes and i've looked everywhere to find it on the internet!!!!!!


1. why is the actual mechanical advantage of a machine different from a machines ideal mechanical advantage?

2. What do you need to know to calculate the effiency of a machine?

3. Can a machine increase both force and distance? explain.

4. Make a comparison table: one increases force and one that increase distance. For each machine compare x and y force and work.

Answer 1

1. Energy is lost to friction in the machine.

2. You need the effort force, effort distance, resistance force, and the resistance distance. This is needed because the ideal mechanical advantage is (effort distance) / (resistance distance) and the actual mechanical advantage is (resistance force) / (effort force), and the efficiency is (actual mechanical advantage) / (ideal mechanical advantage). Or you need the effort work and the resistance work, because efficiency is also (resistance work) / (effort work).

3. No it cannot. A machine cannot output more work than is put into it. But if both distance and force increased, work would increase, too, since work = force x distance.

4. Assuming an ideal machine, force and distance would have a constant product. Suppose the effort work were 100 J, with an effort force of 50 N and an effort distance of 2m. You could increase the resistance force to 100 N and get a resistance diance of 1 m, 200 N for 0.5 m, 500 N for 0.2 m, and so forth. You could increase the resistance distance to 5 m and get a resistance force of 20 N, 10 m for 10 N, 20 m for 5 N, and so forth. If you have specific numbers in this problem, you should use them.

Answer 2

1. Ideal mechanical advantage does not count friction.

2 (work output / work input) x 100 OR (actual mechanical advantage) / (ideal mechanical advantage)

3. No then the work input must be greater than work output.