Middle School Physical Science : Middle School Physical Science
Study concepts, example questions & explanations for Middle School Physical Science
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Example Questions
Example Question #10 : Identify Where Potential Energy Is Least Or Greatest As An Object Changes Position
A skiier wants to go down a slope with the most kinetic energy possible. The best way to go faster is to start higher up. Why is this?
Starting higher up will require less potential energy as the skieer goes down.
Starting higher up will start them with more potential energy, which is converted to kinetic energy later.
Starting higher up will start them with more potential energy, which will stay constant as the skiier goes down the slope.
Starting higher up will start them with more kinetic energy.
Starting higher up will start them with more potential energy, which is converted to kinetic energy later.
The answer is "Starting higher up will start them with more potential energy, which is converted to kinetic energy later."
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.
Example Question #1 : Describe The Relationships Between Kinetic Energy, Mass, And Speed
A monster truck is traveling at 100 meters per second and runs straight into a bike (with no one on it) The bike is traveling towards the truck at 5 meters per second. As expected, the bike goes flying because it has less kinetic energy than the monster truck. How fast would the bike have to be going to make the monster truck go flying instead?
there is not enough information because we don't know the mass of either object
the bike would have to be going 150 meters per second or more
the bike would never send the monster truck flying
the bike would have to be going 101 meters per second or more
there is not enough information because we don't know the mass of either object
The answer is "there is not enough information because we don't know the mass of either object."
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.
Example Question #1 : Describe The Relationships Between Kinetic Energy, Mass, And Speed
What is the kinetic energy of a 4 kilogram book, falling at 5 meters per second?
10 Joules
100 Joules
5 Joules
50 Joules
50 Joules
The answer is 50 Joules. The equation for Kinetic Energy is: KE = 1/2 mv2 and 1/2 of 4 x 52 = 50.
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.
Example Question #21 : Potential And Kinetic Energy
If two cars of the same mass get in a head on collision, which car will likely damage the other more? (ignore vehicle design and assume transferring more kinetic energy results in more damage)
the car with a colder temperature
the car with a warmer temperature
the car going fastest
the car going slowest
the car going fastest
The answer is "the car going fastest"
Example Question #1 : Describe The Relationships Between Kinetic Energy, Mass, And Speed
You serve a volleyball with a mass of 2.1 kg. The ball leaves your hand with a speed of 30 m/s. What is the kinetic energy of the ball?
9.45 Joules
945 Joules
900 Joules
1890 Joules
945 Joules
The answer is 945 Joules. 1/2 of 2.1 x 302 = 945.
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.
Example Question #5 : Describe The Relationships Between Kinetic Energy, Mass, And Speed
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 increase because more mass will need more force to push.
The kinetic energy of the cart will stay the same because 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 increase because the mass is increasing while the speed remains constant.
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.
Example Question #1 : Describe The Relationships Between Kinetic Energy, Mass, And Speed
True or false: If an object has more speed than something else, it definitely has more kinetic energy.
false
true
false
The answer is false. An object with less speed and more mass could potentially have the same Kinetic energy.
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.
Example Question #3 : Describe The Relationships Between Kinetic Energy, Mass, And Speed
If an object has 250 Joules of Kinetic energy and is traveling at a velocity of 5 meters per second, what is the objects mass?
20 kg
1000 kg
25 kg
2 kg
20 kg
The object has a mass of 20kg. Rearranging the formula for kinetic energy will allow you to work backwards. 250 Joules x 2 = 500 Joules. 500 Joules divided by the velocity squared (25) = 20 kg.
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.
Example Question #21 : Potential And Kinetic Energy
If a duck is flying at 3 meters per second, and has a mass of 2kg. What is the kinetic energy of the duck?
6 Joules
24 Joules
12 Joules
3 Joules
6 Joules
The duck has a kinetic energy of 6 Joules.
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.
Example Question #22 : Potential And Kinetic Energy
The equation for Kinetic Energy is: KE = 1/2 mv2 . Based on this equation, what would have the greatest impact on the overall kinetic energy of a moving object?
applying more force
increasing the velocity
applying less force
increasing the mass
increasing the velocity
The answer is increasing the velocity, because the velocity variable is squared and therefore an increase in velocity would have a greater impact on the overall kinetic energy.
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.
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