The elevation at the base of a ski hill is 350 m above sea level. A ski lift raises a skier (total mass = 72 kg, including equipment) to the top of the hill. If the skier’s gravitational potential energy relative to the base of the hill is now 9.2 × 105 J, what is the elevation at the top of the hill?

Question

jamesj · Answer

What is the expression for gravitational potential energy, PE, in terms of mass $ m $, the gravitational acceleration $ g $ and the height $ h $ ?

anonymous · Answer

$$Eg = mgh$$

jamesj · Answer

Yes, $ PE = mgh $.  Now suppose the skier is raised up an additional $ h $ from the base of the mountain, then you know that 
$$ PE = 9.2 \times 10^5 $$ and $$ PE = mgh. $$  You also know $ m $ and $ g $.  Now solve for $ h $.

Then the elevation of the mountain is $ 350 + h $.

jamesj · Answer

Make sense?

anonymous · Answer

yup, so that means 9.2 x 10^5 / 72 kg / 9.8 N/kg = h?

jamesj · Answer

looks right

anonymous · Answer

then I add 350 to the h to get the elevation?

jamesj · Answer

Yes, it must be, because h measures distance from the base, and the energy level 9.2x10^5 was specified as being " gravitational potential energy relative to the base of the hill "

anonymous · Answer

Oh i see now, so adding on the 350 makes it the height above sea level! Thank a lot dude!