Cause he left out the noble gases out of the periodic table for one good reason, 1: He did not know them
The answer is above but I don't know if it's correct.
IMA stands for ideal mechanical advantage, which is the theoretical force amplification factor on an ideal mechanical device free of friction, deformations, etc.
If the applied force (effort) is 50N, then the force applied to the resistance is multiplied by the IMA=2 to get 100N.
If you're holding the apple at your waist, lift it to your mouth.
Potential energy relative to any level is proportional to its height
above that level. Increase that height, and you've increased the
potential energy.
Since energy is conserved ... it never magically appears or
disappears ... you need to tell where that extra energy for the
apple came from.
It's exactly the work you did ... the force of your muscles acting
through the distance you raised the apple ... that became the
additional potential energy that the apple gained.
Answer: Force = 81 N
Explanation:
from Columbs law,
F = k(q1*q2)/r²
k = 9 x 10^9 Nm²/C²
F = (9 x 10^9)x (0.9x10^-5 x 2.5x10^-4)/(0.5)²
F = 81 Newtons
