The correct answer is A. Installation of rigid metal conduit requires grounding and the grounding equipment used may weaken the structure.
The mechanical advantage is the factor by which
the machine multiplies the input force.
If the MA is 3 and the input force is 630N, then
the output force is
(3) x (630N) = 1,890N
Weight = (mass) x (gravity)
Weight = (7.0 kg) x (gravity)
On Earth, where (gravity) is roughly 10 N/kg . . .
Weight = (7.0 kg) x (roughly 10 N/kg)
Weight = roughly 70 Newtons
That's <em>B </em>on Earth.
It would be some other number on other bodies.
<span>The weightlifter does no work. Although he has exerted force, work is the product of force over distance. Since he has not moved the wall he has done no work.</span>