Checking Up 1. When a spring scale is used to do work pulling a cart to the top of an incline, where has the energy gone when the cart is at rest at the top? 2. Where does the roller coaster get its gravitational potential energy when it is at the top of the first hill? 3. Why do truckers use a ramp when loading a truck if the work required is the same with or without a ramp?

1. When a spring scale is used to do work pulling a cart to the top of an incline, the elastic energy stored in the spring is converted into gravitational potential energy, since the top of an incline has a certain height.

2. The roller coaster get its gravitational potential energy from the kinetic energy it carries when it moves with a certain velocity.

3. Truckers use a ramp because it is easier to load a truck with less applied force. Although the work required is the same, without the ramp the force that they should apply is much greater, hence more difficult.

h is greater than (d x cos(Θ)), hence F2 is smaller than F1.

pe = weightxheight = 2000x1000=2,000,000joules