Kinetic Energy of 840 Kg Roller Coaster Trolley

[x3lifelove]

A roller coaster trolley and its passengers have a mass 840 Kg. The trolly comes over the top of the first hill with a speed of .200 m/s. The hill is 85.0 m above the ground. The trolley goes down the first hill and up the crest of the second hill 64.0 m above ground. Ignore the effects of frictional forces. What is the kinetic energy of the trolly at the top of the second hill?

Help please, I keep getting the answer wrong ):

 

[Clever-Name]

What do you know about conservation of potential and kinetic energy? Look at the height of the roller coaster at the top of each crest.

 

[tiny-tim]

hi x3lifelove!

show us your full calculations, and then we'll see what went wrong, and we'll know how to help!