Which is the best indication of the usefulness of a machine, the ...

[chandani]

Which is the best indication of the usefulness of a machine, the actual mechanical advantage or the theoretical mechanical advantage?

Question 2

A large, metallic, spherical shell has no net charge. It is supported on an insulating stand and has a small hole at the top. A small tack with charge Q is lowered on a silk thread through the hole into the interior of the shell. What is the charge on the outer surface of the shell now?
  1.Q
  2.Q/2
  3.0
  4.-Q/2
  5.-Q

[bubulittle310@msn.cn]

Answer to Question 1

Since machines are generally used to increase the force that can be applied to a load,
the actual mechanical advantage is usually the most useful. The theoretical
mechanical advantage is sometimes useful, however, when the machine in question is
judged by how far the load is moved during its operation.

Answer to Question 2

1

[chandani]

YES! Correct, THANKS for helping me on my review

[cam1229]

Thanks for the timely response, appreciate it