Answer:
1. I, II, III and IV
Explanation:
Potential energy is present in any system that can perform work depending on the conditions it is in.
I) Water behind a dam:
When there is water behind a dam. The water is pushing the dam in all directions with a certain presure. If the dam broke or just disappear, all the water would escape with a lot of energy. This is the potential energy water has and that is contained inside the dam. This is used sometimes to generate electric energy.
II) A swinging pendulum:
This is an interesting application of potential and kinetic energy. When the pendulum is at its highest, the potential energy will be at its maximum. This is given y the formula:
U=mgh
when the pendulum is at its lowest, all this potential energy becomes kinetic energy, given by the equation:
[tex]K=\frac{1}{2}mv^{2}[/tex]
and when the pendulum goes back up, all this kinetic energy becomes potential energy gradually.
III) An apple on an apple tree. The potential energy contained by the apple is given by the formula:
U=mgh
where U is the potential energy, m is the mass, g is the acceleration of gravity and h is the height of the apple.
the energy you get by using this formula is the capacity the apple has to do some work. As the apple falls, this potential energy will gradually become kinetic energy since the apple will be traveling faster than its original velocity.
IV)The space shuttle in orbit.
This system also has potential energy. Actually, that's what avoids the rocket from flying away to outer space. How is so: When something is in orbit, that object is constantly falling towards the center of the earth with a given acceleration which depends on how high the satellite is located at. The satellite doesn't collide against the earth because it has a certain tangent velocity which changes in direction constantly. That's why satellites have a circular motion. The potential energy the space shuttle has can be found by using the potential energy formula:
U=mgh
Answer: 1, 2 and 3
Explanation: Potential energy is "stored energy of the system" so let's analyze each system and see if it has some way of creating energy.
1) The dam is containing the water, and if we open a little hole in the dam (or remove the dam) the water will move because the force of gravity, so there is energy stored, and this means that this system has potential energy.
2) the singing pendulum is already moving, if the pendulum is in the lowest point (where the velocity is the biggest) it has only kinetic energy, if the pendulum is in the highest position (where it changes the direction of movement, which means that at this point it has zero velocity) has only potential energy. In all the other points, it has both, potential and kinetic.
3) The apple is being held by a stem, if we remove the stem, it will fall to the force of gravity, so this has potential energy.
4) The mean that it is in orbit, means that it is in equilibrium, so it moves at a constant velocity and is held in place only by the gravity, so this has no "wall" holding it. There is no potential energy in the system.
