Question

suppose the potential energy of the block at the table is given by mgh/3. this implies that the chosen zero level of potential energy is ______ view available hint(s)
○ a distance h/3 above the floor
○ a distance h/3 below the floor
○ a distance 2h/3 above the floor
○ a distance 2h/3 below the floor
○ on the floor
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Explanation:

The gravitational potential energy is given by \( U = mgy \), where \( y \) is the height relative to the zero - potential level. Let the height of the table above the floor be \( h \), and let the height of the zero - potential level above the floor be \( y_0 \). The height of the table relative to the zero - potential level is \( y=h - y_0 \). We know that \( U=\frac{mgh}{3}=mgy = mg(h - y_0) \).

Divide both sides of the equation \( \frac{mgh}{3}=mg(h - y_0) \) by \( mg \) (assuming \( mg
eq0 \)):
\( \frac{h}{3}=h - y_0 \)

Then, solve for \( y_0 \):
\( y_0=h-\frac{h}{3}=\frac{2h}{3} \)

This means that the zero - potential level is at a height of \( \frac{2h}{3} \) above the floor.

Answer:

C. a distance \( 2h/3 \) above the floor