What data are needed to calculate the actual mechanical advantage of a machine

Explanation:

Mechanical advantage :

Mechanical advantage is equal to the output force divided by input force.

The mechanical advantage is the ratio of the force produced by machine and force applied by it.

Types of mechanical advantage is

(1). Actual mechanical advantage :

Actual mechanical advantage is the ratio of the output force and input force.

(2). Ideal Mechanical advantage :

Ideal mechanical advantage is the ratio of the effort arm and resistance arm.

current flows in a wire

it doesn't. it was imagined up in the middle ages.