Maybe because all of them come from natural elements (sun, air and water)
Here,
Load distance (Ld) = 30 cm
Effort distance (Ed) = 60 cm
Load (L) = 200N
Effort (E) = ?
Now, By using formula,
or, E * Ed = L * Ld
or, E * 60 = 200 * 30
or, E = 6000/60
◆ E = 100N
This is a Right answer...
I hope you understand...
Explanation:
B. All use generators to produce electrical current