Rollercoaster Physics: Calculating Speed and Energy Transformations

[gigglesnicole]

Homework Statement

Rollercoaster cart (55kg) traveling at a velocity of 5m/s reaches position at top of a rollercoaster hill, 5m high.

1. assuming no friction, what would the speed of the cart be at the bottom of the track?
2. at the bottom, the speedometer of the cart displays a speed of 10m/s. What does this suggest about the energy transformation that has occurred as the cart went down the slope?
3. what is the energy efficiency of the cart as it goes down the slope?

Homework Equations

The Attempt at a Solution

already calculated
gravitational potential energy: GPE = m*g*h = 2695
kinetic energy: KE = 1/2*m*v^2 = 687.5

 

[tomwilliam]

So the total energy of the cart is the sum of the kinetic and gravitational potential energy. That total will stay the same. At the bottom of the track, the potential energy will have declined by mg(h1-h2) and the kinetic energy must increase by the same amount. Once you've calculated the increase in kinetic energy you can calculate the new speed.

 

[gigglesnicole]

thanx :) that really helped