# Physics ~Conservation of Energy~ part 2

posted by
**Isis**
.

1.) A 500 kg roller coaster is pulled to the top of a hill 45 m high and arrives at the top with a zero speed.

a) how much work has done by the vhain to pull the car to the top?

b) how much potential energy does it have at the top?

c)What is the total energy of the system?

d) how much kinetic energy does it have at the bottom?

e) what is the speed at the bottom?

2.) A simple pendelum is 1.5 m long and has 3.0 kg bob attached.

a) how much work was done by the chain to pull the car to the top?

b) how much potential energy does it have to the top?

c) what is the total energy of the system?

d) how much kinetic energy does it have at the bottom?

>> FORMULAS <<

KE= 1/2 v^2 (kinetic energy)

PE=mgh (potential energy)

kg.m/s^2.m

W= Fd (work equals force and distance)

Im sorry I don't know which formula to choose. PLease please please help me!