IB Physics SL A 3 10 Gravitational Potential Energy Topic Practice

difference in height of centre of mass of water $=\frac{1.8}{2}=0.9(\mathrm{~m})$;
$\Delta E_{\mathrm{P}}\left(=m g \Delta h=2.8 \times 10^{8} \times 9.8 \times 0.9\right)=2.5 \times 10^{9}(\mathrm{~J}) ;$
electrical energy $\left(=0.24 \times 2.5 \times 10^{9}\right)=5.9 \times 10^{8}(\mathrm{~J})(=590 \mathrm{MJ})$;

Marking guidance:

Allow ECF for [2 max] if candidate omits factor of 2 in first marking points.
Accept $g=10 \mathrm{~m} \mathrm{~s}^{-2}$ giving an answer of $6.0 \times 10^{8}(\mathrm{~J})$.