Question

A sled with rider having a combined mass of 110 kg travels over the perfectly smooth icy hill shown in the accompanying figure.
http://session.masteringphysics.com/problemAsset/1266926/1/1027475.jpg

How far does the sled land from the foot of the cliff?

Answer 1

Remember that the total energy of a system is conserved if all the energy stays within the system. We know that it is, since the ice is "perfectly smooth" so no energy is lost through friction. \[K _{i}+U _{i}=K _{f}+U _{f}\]\[K=(1/2)mv^2\]\[U=mgh\]
So from here you can start to figure out the initial and final potential and kinetic energies to find out the velocity at the top of the hill.

From there you can take it as a regular translational motion problem and solve for the hang time it takes for the sled to fall in the y-direction due to gravity. Once you know how long it'll be in the air, just use that time to calculate how far the sled will travel at the speed it left the top of the hill and you will be able to predict how far it traveled before touching the ground and killing the poor girl on the sled.

Good luck! I can help you anywhere with anything that seems unclear!

Answer 2

Whoops, when I read it I originally thought it said 110m not 11.0m. I guess she's only slightly less likely to die.