Potential and Kinetic Energy
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Middle School Physical Science › Potential and Kinetic Energy
The equation for Kinetic Energy is: KE = 1/2 mv2. What effect would decreasing the mass have on the velocity assuming that the kinetic energy stays the same?
the velocity would decrease
the velocity would increase
the velocity would stay the same
not enough information
Explanation
The velocity would decrease because mass and velocity are inversely related.
The equation for Kinetic Energy is: KE = 1/2 mv2. Kinetic energy has a direct relationship with mass, meaning that as mass increases so does the Kinetic Energy of an object. The same is true of velocity. However, mass and velocity are indirectly related. Objects with greater mass can have more kinetic energy even if they are moving more slowly, and objects moving at much greater speeds can have more kinetic energy even if they have less mass. We must consider both the speed and mass of objects when considering the outcomes of collisions.
The image shows a rollercoaster track. At which point does the rollercoaster have the LEAST potential energy?
position B
position A
position C
none of these
Explanation
The answer is position B, because it is at its lowest point.
Potential Energy is “stored energy.” It is energy that is ready to be converted or released as another type of energy. We most often think of potential energy as gravitational potential energy. When objects are higher up, they are ready to fall back down. When you stretch an object and it has a tendency to return to its original shape, it is said to have elastic potential energy. Chemical potential energy is the stored energy in a substance’s chemical structure that can be released in a chemical reaction or as heat.
Potential energy is greatest when the most energy is stored. This could be when an object reaches its highest point in the air before falling, a rollercoaster just before it drops, or when a rubber band is stretched as far back as possible before it snaps. Potential energy is then converted to kinetic energy.
The equation for Kinetic Energy is: KE = 1/2 mv2. What effect would decreasing the mass have on the velocity assuming that the kinetic energy stays the same?
the velocity would decrease
the velocity would increase
the velocity would stay the same
not enough information
Explanation
The velocity would decrease because mass and velocity are inversely related.
The equation for Kinetic Energy is: KE = 1/2 mv2. Kinetic energy has a direct relationship with mass, meaning that as mass increases so does the Kinetic Energy of an object. The same is true of velocity. However, mass and velocity are indirectly related. Objects with greater mass can have more kinetic energy even if they are moving more slowly, and objects moving at much greater speeds can have more kinetic energy even if they have less mass. We must consider both the speed and mass of objects when considering the outcomes of collisions.
What is one way we could increase the gravitational pull between these two objects?
increase the mass
put them closer together
both of these
neither of these
Explanation
The answer is "both of these."
Gravitational energy exists between all objects. We rarely talk about the gravitational energy that exists between objects here on Earth because the pull is so weak. We consider the effect of gravity more often when we talk about planets, stars, and galaxies because they are more massive and have much stronger forces of gravity at work.
The gravitational potential energy of an object depends on the mass of objects, and how far away they are from each other. More massive objects have more gravitational pull. (Remember that just because something is bigger, doesn’t mean it has more mass!) Objects that are closer together have more gravitational pull.
Weight is a measure of the effect of gravity on an object, and can change depending on where we are. Our mass never changes but we weigh less on the moon because there is less gravitational energy between us and the moon. The moon has less gravitational energy than Earth because it is less massive.
The image shows a rollercoaster track. At which point does the rollercoaster have the LEAST potential energy?
position B
position A
position C
none of these
Explanation
The answer is position B, because it is at its lowest point.
Potential Energy is “stored energy.” It is energy that is ready to be converted or released as another type of energy. We most often think of potential energy as gravitational potential energy. When objects are higher up, they are ready to fall back down. When you stretch an object and it has a tendency to return to its original shape, it is said to have elastic potential energy. Chemical potential energy is the stored energy in a substance’s chemical structure that can be released in a chemical reaction or as heat.
Potential energy is greatest when the most energy is stored. This could be when an object reaches its highest point in the air before falling, a rollercoaster just before it drops, or when a rubber band is stretched as far back as possible before it snaps. Potential energy is then converted to kinetic energy.
What is one way we could increase the gravitational pull between these two objects?
increase the mass
put them closer together
both of these
neither of these
Explanation
The answer is "both of these."
Gravitational energy exists between all objects. We rarely talk about the gravitational energy that exists between objects here on Earth because the pull is so weak. We consider the effect of gravity more often when we talk about planets, stars, and galaxies because they are more massive and have much stronger forces of gravity at work.
The gravitational potential energy of an object depends on the mass of objects, and how far away they are from each other. More massive objects have more gravitational pull. (Remember that just because something is bigger, doesn’t mean it has more mass!) Objects that are closer together have more gravitational pull.
Weight is a measure of the effect of gravity on an object, and can change depending on where we are. Our mass never changes but we weigh less on the moon because there is less gravitational energy between us and the moon. The moon has less gravitational energy than Earth because it is less massive.
Chemical potential energy is stored in the bonds between atoms. This means that chemical potential energy is greatest when:
before a chemical reaction occurs
after a chemical reaction occurs
when the chemical is being created
none of these
Explanation
The answer is "before a chemical reaction occurs."
Potential Energy is “stored energy.” It is energy that is ready to be converted or released as another type of energy. We most often think of potential energy as gravitational potential energy. When objects are higher up, they are ready to fall back down. When you stretch an object and it has a tendency to return to its original shape, it is said to have elastic potential energy. Chemical potential energy is the stored energy in a substance’s chemical structure that can be released in a chemical reaction or as heat.
Potential energy is greatest when the most energy is stored. This could be when an object reaches its highest point in the air before falling, a rollercoaster just before it drops, or when a rubber band is stretched as far back as possible before it snaps. Potential energy is then converted to kinetic energy.
Suppose you have a grocery cart. You are pushing it down the aisle and you continue to push with the same speed as you put more items in the cart. As you add more groceries to the cart, how will the Kinetic energy of the cart change?
The kinetic energy of the cart will increase because the mass is increasing while the speed remains constant.
The kinetic energy of the cart will decrease because the mass is increasing while the speed remains constant.
The kinetic energy of the cart will stay the same because the speed remains constant.
The kinetic energy of the cart will increase because more mass will need more force to push.
Explanation
The kinetic energy of the cart will increase because the mass is increasing while the speed remains constant.
The equation for Kinetic Energy is: KE = 1/2 mv2. Kinetic energy has a direct relationship with mass, meaning that as mass increases so does the Kinetic Energy of an object. The same is true of velocity. However, mass and velocity are indirectly related. Objects with greater mass can have more kinetic energy even if they are moving more slowly, and objects moving at much greater speeds can have more kinetic energy even if they have less mass. We must consider both the speed and mass of objects when considering the outcomes of collisions.
Suppose you have a grocery cart. You are pushing it down the aisle and you continue to push with the same speed as you put more items in the cart. As you add more groceries to the cart, how will the Kinetic energy of the cart change?
The kinetic energy of the cart will increase because the mass is increasing while the speed remains constant.
The kinetic energy of the cart will decrease because the mass is increasing while the speed remains constant.
The kinetic energy of the cart will stay the same because the speed remains constant.
The kinetic energy of the cart will increase because more mass will need more force to push.
Explanation
The kinetic energy of the cart will increase because the mass is increasing while the speed remains constant.
The equation for Kinetic Energy is: KE = 1/2 mv2. Kinetic energy has a direct relationship with mass, meaning that as mass increases so does the Kinetic Energy of an object. The same is true of velocity. However, mass and velocity are indirectly related. Objects with greater mass can have more kinetic energy even if they are moving more slowly, and objects moving at much greater speeds can have more kinetic energy even if they have less mass. We must consider both the speed and mass of objects when considering the outcomes of collisions.
Assuming all of these objects have the same mass, which of these sets of objects would have a greater gravitational potential energy?
the objects that are 10 meters apart
the objects that are 100 meters apart
they have the same gravitational energy
it would depend on the temperature of the objects
Explanation
The answer is "the objects that are 10 meters apart" because they are closer together and thus have a greater gravitational energy between them.
Gravitational energy exists between all objects. We rarely talk about the gravitational energy that exists between objects here on Earth because the pull is so weak. We consider the effect of gravity more often when we talk about planets, stars, and galaxies because they are more massive and have much stronger forces of gravity at work.
The gravitational potential energy of an object depends on the mass of objects, and how far away they are from each other. More massive objects have more gravitational pull. (Remember that just because something is bigger, doesn’t mean it has more mass!) Objects that are closer together have more gravitational pull.
Weight is a measure of the effect of gravity on an object, and can change depending on where we are. Our mass never changes but we weigh less on the moon because there is less gravitational energy between us and the moon. The moon has less gravitational energy than Earth because it is less massive.