Potential and Kinetic Energy

Potential and kinetic energy. Potential energy is the amount of energy an object has stored due to its position orientation. Potential energy is how much energy something has; it’s just sitting still, it’s just stored.

It is not in motion, it’s how much energy an object could have if it’s moved, it’s potential energy and gravity most commonly affects potential energy.

Mini-test: POTENTIAL ENERGY 

Question 1: Which of the following objects has the most potential energy?
A.  
B.  
C.  
D.  
Question 2: If you lift 2 kg block of cheese out of the fridge, stumble, and drop it from hip height (about .8 meters), what is its potential energy? (You are on earth, and the acceleration of gravity is 9.8 m/s2.)
A.  
B.  
C.  
D.  

 

Next lesson: Forces Push Pull

The following transcript is provided for your convenience.

There are other factors, such as mass that can affect potential energy, but the force of gravity on an object is going to affect it the most. If an object is up higher, it’s going to have more potential energy than an object that is down lower, because the lower object is going to have a smaller amount space to fall. The higher object is going to have a further way to fall and so it’s going to have more potential energy. The formula for finding potential energy, P stands for potential energy equals M. G, H.

M stands for mass, G stands for acceleration of gravity, so the force that gravity is going to have on that object and H stands for height. You’re going to multiply the mass of the object times the acceleration of gravity times the height from which it is from the ground and that is going to give you your potential energy. You can say that the acceleration of gravity and the height, the distance an object is from the ground are both big parts in this formula for finding potential energy, so gravity is very important to the potential energy in an object.

Potential energy is how much energy an object has stored, while it’s sitting still. Kinetic energy is the energy of an object in motion, so when an object is actually moving, that is whenever you’re seeing kinetic energy. Kinetic energy KE can be found with this formula, MV squared divided by two, where M equals the mass and V equals velocity. Mass times the velocity squared divided by two, will give you the kinetic energy of an object. This one doesn’t have much to do with gravity because once it’s in motion, the kinetic energy has more to do with the velocity and the mass of the object.

Let’s look at this, say we’ve got this little situation set up, you build this side of wood, Legos or something and you’ve got a ball and you’re going to roll it down hill, so when you’re ball is here you have potential energy, it’s sitting still. Once its goes over the edge and you have it here, you have kinetic energy because this ball is in motion. If it moves down some more and sits still for a minute, you’re going to have potential energy as its sitting still, because it could still go down some more and if it does, then you have kinetic energy again because this ball is rolling, it’s in motion.

Then if it lands here you’ve got potential energy, because it can still drop off the edge. Potential energy is energy that is stored while an object is still. Kinetic energy is the energy of motion, when something is actually moving, and while potential energy is still stored, kinetic is moving in motion.

Next lesson: Forces Push Pull

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