You are riding on a roller coaster that starts from rest at a height of 25.0 m and moves down a frictionless track to a height of 3.00 m.

how fast are you moving when you arrive at the 3.00-m height? - 22.1 m/s
- 20.8 m/s
- 23.4 m/s
- 14.7 m/s

To solve this problem, we need to use both energy conservation and potential kinetic equations.

When the energy accumulated from a certain height is released, it becomes 'motion' energy or kinetic energy. Mathematically this can be expressed as

PE = KE

Where

m = mass

g = Gravitational acceleration

v = Velocity

Change of the height

We know that the body, based on a reference system where the floor is the zero coordinate, starts from being 25 meters high to fall to 3 meters high, so the total difference in height would be

We also have to

Using the previous equation we have to:

Replacing

The correct answer is 20.8m/s

r=rho l/a where a is the area, l is the length and rho is resistivity so the greater the area the lesser the resistance thats why the earth pin is thicker bcos current follow the shortest path, so less resistive .

chemical properties of thing