Question

Calculate the change in the gravitational potential energy of the skier between $A$ and $B$:

• A. $1.8\times {10}^{4}J$
• B. $3.6\times {10}^{2}J$
• C. $3.6\times {10}^{4}J$
• D. $1.8\times {10}^{2}J$

Answer 1

Answer: (C)

$3.6\times {10}^{4}J$

Weight of the skier $=$ $60kgf$
Mass of the skier $=$ $60kg$
Initial gravitational P.E. of skier $=$ $mgh$
$=60\times 10\times 75=$ $45000J$
Final gravitational P.E. of skier $=60\times 10\times 15=9000J$
change in the gravitational potential energy of the skier between A and B

$=(45000-9000)J=$ $36000J$

$=3.6\times {10}^{4}J$