A roller coaster with people on board has a total mass of 4500 kg and starts at a height of 22 meters with a speed of 2.0 m/s. 50 kJ of work is done by friction on the way to the bottom of the ride. What is the speed at the bottom of the ride?

Question

A roller coaster with people on board has a total mass of 4500 kg and starts at a height of 22 meters with a speed of 2.0 m/s.  50 kJ of work is done by friction on the way to the bottom of the ride. What is the speed at the bottom of the ride?

I'm LOST...no clue how to start exam Monday :(

mssailormouth · Accepted Answer

KE bottom KE top=PE top -friction 1/2(4500)v^2=4500(9.8)(22) -50000 v=20

bobpursley · Answer

KE at bottom=KE at top + PE at top -work done by friction

mssailormouth · Answer

I've got a huge number this cannot be right. 1/2(4500)(2.0)^2 + 4500(9.8)(22)-50000=929200?????