Match these items as to type of energy, whether kinetic, potential, or both.

1) a rock at the edge of a
2) a plane in flight at 30,000
3) water behind a
4) water flowing
5) a car moving on a level
6) a compressed
7) a child on a
8) a bouncing

Before answering the question, let's remind the difference between kinetic energy and potential energy:

- Kinetic energy: it is the energy due to the motion of an object. It is given by

where m is the mass and v is the speed: so, an object has kinetic energy whenever it is in motion

- Potential energy: it is the energy due to the position of an object. It can be of different types:

-- Gravitational potential energy: due to the height h of an object with respect to the ground

-- Elastic potential energy: energy stored by a compressed/stretched spring

Keeping in mind these definitions, let's now analyze each case:

1) a rock at the edge of a cliff...  --> potential energy (because it has some height h above the ground, while it is at rest, so no kinetic energy)

2) a plane in flight at 30,000 feet...  --> both potential and kinetic energy (because it has some height h above the ground and it is also moving)

3) water behind a dam...  --> potential energy (because it has some height h above the ground, while it is at rest, so no kinetic energy)

4) water flowing downstream...  --> both potential and kinetic energy (because it has some height h above the ground and it is also moving)

5) a car moving on a level road...  --> kinetic energy (because it is moving, while it has no height h above the ground, so no potential energy)

6) a compressed spring...  --> potential energy (elastic potential energy)

7) a child on a swing...  --> both potential and kinetic energy (because it has some height h above the ground and it is also moving)

8) a bouncing ball... --> both potential and kinetic energy (because it has some height h above the ground and it is also moving)

because it says use -2,0,and 2 for x, we can plug those numbers into the equation. y/4=3/4(-2)+2   y/4= -1 1/2 +2 now to get x by itself, we can multiply each side by 4. y=-6+8 which equals y=2 when x=-2. now you can do the same thing with 0 and 2 as x. you get y=8 when x=0 and y=14 when x=2.

x   |   y

-2 |   2

0   |   8

2   |   14