1.
A bowling ball and a ping pong ball are rolled down a hallway at identical velocities. Which one has the greater kinetic energy (KE)?
Correct Answer
A. The bowling ball has more KE
Explanation
The bowling ball has more kinetic energy because kinetic energy is directly proportional to an object's mass. Since the bowling ball is much heavier than the ping pong ball, it will have a greater kinetic energy.
2.
Felix the cat sits on a branch 20 feet above the ground. Felix's identical twin brother cat named Helix sits on a branch 10 feet above the ground. If the two cats have identical masses, which cat has greater potential energy (PE)?
Correct Answer
B. Felix has more PE
Explanation
Felix has more potential energy because potential energy is directly proportional to the height above the ground. Since Felix is sitting on a branch that is 20 feet above the ground, he has a greater height and therefore greater potential energy compared to Helix, who is sitting on a branch that is only 10 feet above the ground.
3.
Ironman and Wolverine enter the roller derby (a race on rollerblades). The superheros happen to have identical masses. However, Ironman is an expert rollerblader and Wolverine is a beginner, so Ironman's speed is four times faster than Wolverine's speed. How much greater is Ironman's kinetic energy (KE) than Woverine's KE?
Correct Answer
D. 16 times greater
Explanation
Ironman's kinetic energy is 16 times greater than Wolverine's kinetic energy because kinetic energy is directly proportional to the square of an object's speed. Since Ironman's speed is four times faster than Wolverine's speed, his kinetic energy is (4^2) = 16 times greater.
4.
Mickey carries her ipod up a ladder. Which has greater potential energy on the top rung of the ladder, Mickey or her ipod?
Correct Answer
A. Mickey
Explanation
Mickey has greater potential energy on the top rung of the ladder compared to her iPod. Potential energy depends on the height and mass of an object. Since Mickey is carrying her iPod up the ladder, she is higher off the ground and therefore has a greater potential energy. The iPod, being smaller and lighter, has less potential energy in comparison.
5.
Alyssa's pet iguana is sitting on the windowsill of a two story building. If the windowsill is exactly 3.5 m above the ground, and the iguana has a mass of exactly 10 kg, what is its potential energy? (Remember, g=9.8 m/s2 and PE = mgh.)
Correct Answer
D. 343 J
Explanation
The potential energy of an object is given by the equation PE = mgh, where m is the mass of the object, g is the acceleration due to gravity, and h is the height of the object above a reference point. In this case, the iguana has a mass of 10 kg and is sitting on a windowsill that is 3.5 m above the ground. Plugging these values into the equation, we get PE = (10 kg)(9.8 m/s^2)(3.5 m) = 343 J. Therefore, the potential energy of the iguana is 343 J.
6.
A 1-gallon can of paint is sitting on the top of a ladder, exactly 2 m above the ground. If its potential energy is 39.2 J, find its mass. (Use g = 9.8 m/s2 and PE = mgh.)
Correct Answer
C. 2 kg
Explanation
The potential energy of an object is given by the equation PE = mgh, where m is the mass of the object, g is the acceleration due to gravity, and h is the height of the object. In this case, the potential energy is given as 39.2 J and the height is 2 m. By rearranging the equation, we can solve for the mass: m = PE / (gh). Plugging in the given values, we get m = 39.2 J / (9.8 m/s^2 * 2 m) = 2 kg. Therefore, the mass of the paint can is 2 kg.
7.
A baseball player wants to hit more homeruns. As his coach, you tell him he needs to hit the ball with more kinetic energy. He could either get a bat with twice as much mass or he could swing his current bat with twice as much velocity. Assuming his accuracy stays the same, which would help him hit the ball further?
Correct Answer
B. A faster swing
Explanation
A faster swing would help the baseball player hit the ball further because kinetic energy is directly proportional to the square of the velocity. Doubling the velocity of the swing would result in four times the kinetic energy, which would transfer to the ball upon impact and increase the distance it travels. Increasing the mass of the bat would only increase the momentum, but not the kinetic energy, which is the key factor in determining the distance the ball will travel.
8.
The SI unit for energy is the
Correct Answer
D. Joule
Explanation
The correct answer is Joule because the joule is the SI unit for energy. It is named after the English physicist James Prescott Joule and is defined as the amount of work done when a force of one newton is applied over a distance of one meter. The joule is commonly used to measure various forms of energy such as mechanical, electrical, and thermal energy.
9.
Energy can change form from one type to another.
Correct Answer
A. True
Explanation
Energy can change form from one type to another. This is known as the principle of energy conversion. Energy can be transformed from potential to kinetic, thermal to mechanical, electrical to chemical, and so on. This concept is fundamental in understanding various natural phenomena and technological applications. It is supported by scientific evidence and observations, making the statement true.
10.
Energy is defined as
Correct Answer
D. All of the above
Explanation
Energy is defined as the ability to do work, which refers to the capacity to exert force and move an object. It is also the ability to produce heat, as energy can be converted into thermal energy through processes such as combustion. Additionally, energy has the ability to cause change, as it can bring about transformations in various forms, such as chemical reactions or the movement of objects. Therefore, the correct answer is "all of the above" as energy encompasses these different abilities.
11.
Kinetic energy is defined as the energy of
Correct Answer
C. Motion
Explanation
Kinetic energy is the energy possessed by an object due to its motion. When an object is in motion, it has the ability to do work and transfer energy to other objects. Therefore, the correct answer is motion because kinetic energy is directly related to the movement of an object.
12.
Potential energy is the energy of
Correct Answer
B. Storage
Explanation
Potential energy refers to the stored energy possessed by an object due to its position or state. In this context, "storage" is the correct answer as it accurately describes the concept of potential energy. The other options, such as electricity, heat, and motion, are forms or manifestations of energy, but they do not directly represent the concept of potential energy itself.
13.
Thermal energy is the energy of
Correct Answer
B. Particles in motion
Explanation
Thermal energy refers to the energy possessed by the particles of a substance due to their motion. When particles are in motion, they collide with each other and transfer energy, resulting in an increase in temperature. This energy is responsible for the sensation of heat and is commonly used for heating purposes. The other options, such as bonds between molecules, storage, and electricity, do not accurately describe thermal energy.
14.
Amorette connects a battery to a motor and the motor starts spinning. This is an example of electrical energy being transformed into
Correct Answer
A. Kinetic energy
Explanation
When Amorette connects a battery to a motor and the motor starts spinning, it indicates the transformation of electrical energy into kinetic energy. The electrical energy from the battery is converted into mechanical energy, causing the motor to move and generate motion, which is the definition of kinetic energy.
15.
Gabby connects a battery to a motor and the motor starts spinning. Then, she disconnects the battery from the motor. The disconnected battery is an example of what type of energy?
Correct Answer
B. Potential
Explanation
When Gabby disconnects the battery from the motor, the battery still holds stored energy that can be used to do work in the future. This stored energy is known as potential energy.
16.
Ms. Van Rhoads holds a book in the air. It is perfectly still. It has what type of energy?
Correct Answer
A. Potential
Explanation
The book being held in the air by Ms. Van Rhoads has potential energy. Potential energy is the energy possessed by an object due to its position or state. In this case, the book has the potential to fall down and release energy due to gravity. Since the book is perfectly still, it is not in motion, therefore it does not have kinetic energy. Nuclear and chemical energy are not relevant in this scenario.
17.
Ms. Van Rhoads drops a book. While it is falling, what type of energy does it have?
Correct Answer
B. Kinetic
Explanation
When Ms. Van Rhoads drops a book, it is in motion and therefore has kinetic energy. Kinetic energy is the energy possessed by an object due to its motion. As the book falls, its potential energy decreases and is converted into kinetic energy.
18.
Ms. Van Rhoads drops a book. When the book hits the ground, it makes a loud "thud" sound. Sound is really a form of _________ energy because it is the motion of air compressing and expanding.
Correct Answer
C. Kinetic
Explanation
When the book hits the ground, it creates a disturbance in the air molecules, causing them to compress and expand rapidly. This compression and expansion of air molecules is what we perceive as sound. Since sound is the result of the motion of air molecules, it is a form of kinetic energy.
19.
The difference between nuclear energy and chemical energy is that
Correct Answer
A. Nuclear energy is stored in the bonds between protons and neutrons in an atom but chemical energy involves the bonds between atoms
Explanation
The correct answer is that nuclear energy is stored in the bonds between protons and neutrons in an atom, while chemical energy involves the bonds between atoms. This explanation highlights the fundamental difference between nuclear energy and chemical energy, emphasizing the location of energy storage in each case. Nuclear energy is stored within the nucleus of an atom, specifically in the bonds between protons and neutrons, while chemical energy is stored in the bonds between atoms in a molecule.
20.
Your little brother is jumping on the bed. The mattress has springs inside. When he lands on the bed, he compresses the springs into tight coils. At that exact moment when the spring is completely compressed, what type of energy does it have?
Correct Answer
C. Potential
Explanation
When the spring is completely compressed, it has potential energy. Potential energy is stored energy that an object possesses due to its position or condition. In this case, the spring is compressed, which means it is in a state where it can do work or exert force when released. The potential energy is stored in the tight coils of the spring and can be converted into kinetic energy when the spring is released and returns to its original shape.
21.
Your little brother is jumping on the bed. The mattress has springs inside. When he lands on the bed, he compresses the springs into tight coils. Then, the spring does what springs do -- it stretches back out and sends your little brother flying into the air. While the spring is in the process of stretching, what type of energy does it have?
Correct Answer
D. Kinetic
Explanation
When the spring is in the process of stretching, it has kinetic energy. This is because kinetic energy is the energy possessed by an object due to its motion. In this case, as the spring stretches back out, it is in motion, and therefore it has kinetic energy.
22.
A baseball is thrown at 24 m/sec. If it has a kinetic energy of 43.2 J, what is the mass of the baseball? KE = 1/2 mv2 . Don't forget units!
Correct Answer
.15 kg
0.15 kg
.15kg
0.15kg
150 g
Explanation
The kinetic energy formula is KE = 1/2 mv^2, where KE is the kinetic energy, m is the mass, and v is the velocity. Rearranging the formula, we have m = 2KE/v^2. Given that the kinetic energy is 43.2 J and the velocity is 24 m/s, we can substitute these values into the formula to find the mass. m = 2(43.2) / (24)^2 = 0.15 kg. Therefore, the correct answer is 0.15 kg.
23.
Natasha pitches a softball at a speed of 30 m/sec. If the ball has a mass of 0.18 kg, what is the kinetic energy of the ball as it crosses home plate? Include units! (KE = 1/2 mv2 .)
Correct Answer
81 J
81J
81 j
81j
81 Joules
Explanation
The kinetic energy of an object is given by the formula KE = 1/2 mv^2, where m is the mass of the object and v is its velocity. In this case, the mass of the softball is given as 0.18 kg and its velocity is given as 30 m/s. Plugging these values into the formula, we get KE = 1/2 * 0.18 kg * (30 m/s)^2 = 81 J. Therefore, the kinetic energy of the ball as it crosses home plate is 81 Joules.
24.
Work is a form of energy.
Correct Answer
A. True
Explanation
Work is a form of energy because it involves the transfer or transformation of energy. When work is done on an object, energy is transferred to that object, causing it to move or change in some way. This transfer of energy is what allows work to be done. Therefore, work and energy are closely related and can be considered different forms of the same concept.
25.
At the beginning of each Science class, we find our pulses and breathe. We do this in order to
Correct Answer
C. Tame our monkeys
26.
Hello, Students,
I will not be at school today to show my support of the immigration bill protest in Phoenix. Several of my students have asked me to join the walk out, and I agree with you/them. I will be driving to Phoenix to participate in the vigil outside Jan Brewers office.
This protest fits well into the junior's history curriculum, because we are about to study the period from 1800-1860 of manifest destiny, and the changing of the borders that removed the Southwest from Mexico and annexed this area to the US. Who has a "right" to live here and why? It's not fair, and it hasn't been fair for hundreds of years. If we study history for any useful reason, it should be so we know why things are the way they are, and what we can do to change the things that aren't fair.
http://standing-firm.com/2010/04/22/no-to-racial-profiling-5-ways-to-help-in-arizona/
I am not familiar with the school's policy, but I am willing to accept the personal consequences in terms of docked pay. When we protest, sometimes the consequences in the short term are difficult, but it's worth it if it can change things for the better over the long term. We do not protest in order to get out of something -- like an excuse not to go to school so we can stay at home and play video games. We protest because we want to live in a better world.
If this issue matters to you and you also choose to walk out, you have my blessing. If you choose not to, that is also a valid decision. Do what you believe. Do it understanding that there may be consequences to you personally.
See you on Tuesday. (Your homework is still due as scheduled, this is not about avoiding responsibility in other areas.)
Ms. Van Rhoads
Correct Answer
A. I have read this. Check A to get credit for this question.
Explanation
The correct answer is "I have read this. Check A to get credit for this question." because the student states that they have read the message and understands the content. They are acknowledging that they have received the information and are ready to proceed with the question.