Two identical masses are moving down a slope. One mass is traveling twice as fast as the other mass. How does the kinetic energy of one mass compare to the other? (1 point)
The faster object has the same kinetic energy as the slower object.
The faster object has less kinetic energy than the slower object.**
The faster object has half as much kinetic energy as the slower object.
The faster object has four times as much kinetic energy as the slower object.
3. A 10.0-kg animal is running at a rate of 3.0 m/s. What is the kinetic energy of the animal? (1 point)
3.3 J
30.0 J
45.0 J
90.0 J**
4. Use the image below to answer the following question.
A photo shows a skateboarder airborne with knees bent and arms extended above a skate ramp.
Which kind of energy transformation occurs when the skater’s board falls back to the ramp? (1 point)
mechanical to gravitational to nuclear
kinetic to potential to electrical
gravitational to kinetic to thermal
mechanical to potential to gravitational**
5. Use the image below to answer the following question.
A soccer player prepares to strike a ball off his chest.
Which kind of energy does the soccer player transfer to the ball?
(1 point)
kinetic**
potential
sound
chemical
6. Use the image below to answer the following question.
A photos shows the tip of a wooden match with a red match head.
Which type of energy is represented here?
(1 point)
thermal
chemical potential
mechanical**
electromagnetic
7. Use the image below to answer the following question.
A tennis ball hits the netting on a racquet, causing the netting to flex.
When a tennis ball smashes into a tennis racket, the ball temporarily changes shape as it compresses against the racket. Which type of energy is temporarily stored with the ball as it is compressed?
(1 point)
elastic potential
kinetic**
electrical
potential
8. Some kayakers coat the bottom of their kayaks with wax to make them more slippery.
Kayakers wax their boats to (1 point)
reduce the work output.
reduce the weight of the kayak.**
reduce their input force.
reduce the speed the boat travels in water.
9. You apply 100.0 N of force to a machine. The machine applies 20.0 N of force to the load. What is the mechanical advantage of the machine? (1 point)
200.0
80.0
5.00**
0.200
10. A construction worker is using his weight to keep a stationary stack of wooden beams from falling. If the construction worker uses 689.0 N of force to hold 10 beams stationary against a wall, how much work does he do? (1 point)
0 J**
0.0150 J
68.9 J
6,890 J
11. Metal cookware often comes with plastic handles. The plastic handles (1 point)
decrease friction.
decrease mechanical advantage.
are insulators.
are conductors.**
12. A satellite in space experiences direct sunlight and heats up. During periods when it receives no direct sunlight, (1 point)
the satellite cools off by radiation.
the satellite cools off by conduction.**
the satellite maintains a constant temperature.
the satellite cools off by convection.
13. Use the image below to answer the following question.
A photo shows a pair of sandals and a sunglass case on a beach.
A beachgoer leaves a pair of sandals on the shore while she swims. When she puts the sandals on again, the bottom of her feet will feel hot because _____. Choose all that apply.
(2 points)
the sandals were warmed by radiation**
heat will transfer to her feet by radiation
heat will transfer away from her feet by conduction
heat will transfer to her feet by conduction
14. Four positively charged particles are at various distances from a positively charged plate. The particles are equally charged and do not influence each other. Which particle has the greatest potential energy?
The bottom of a rectangular area shows a row of positive signs that represent the positively charged plate. Four starburst icons labeled A, B, C, and D represent the positively charged particles. A is closest to the plate; B is farther away than A; C is farther away than B; and D is farther away than C.In row 1, column 1 is labeled upper A, column 2 is labeled upper B,
column 3 is labeled upper C, and column 4 is labeled upper D. In row 2, there is a symbol representing a positively charged ion near the bottom of column 1. The symbol is shaded a different color than the background. In row 2, column 2, the ion symbol is a little higher than it was in column 1. In row 2, column 3, the ion symbol is a little higher than it was in column 2. In row 2, column 4, the ion symbol is near the top of the column. In row 3, all of the columns are merged together. The row is shaded the same color as the ion symbols in row 2, and there are 9 positive signs, spaced evenly across the row. (1 point)
A
B
C**
D
15. Use the image below to answer the following question.
A man prepares to use a bow and arrow by pulling the arrow back against the string of the bow.
Which of the following energy changes occurs as a bow is drawn and released?
(1 point)
gravitational potential to chemical potential**
magnetic potential to kinetic
elastic potential to kinetic
kinetic to thermal
16. Jerri is planning to rebuild the engine of an antique car. She has chosen all the materials she needs, including a high-quality synthetic oil to reduce friction in the engine. What effect will reducing friction have on the engine’s performance? Choose all that apply. (2 points)
Reduced friction means reduced efficiency.
Reduced friction means reduced heat transfer.
Reduced friction means increased efficiency.
Reduced friction means increased heat transfer. **
17. During a space shuttle landing, a parachute deploys from the back of the shuttle as it taxis down the runway. In addition to the speed brake, the parachute helps the shuttle come to a complete stop. How does the parachute help during this process? (1 point)
It increases the weight of the shuttle.
It increases the potential energy of the shuttle.
It increases friction by air resistance.**
It increases heat transfer by radiation.
18. For an experiment, you place 15 g of ice with a temperature of –10oC into a cup and label it A. You also place 25 g of ice at the same temperature into another cup and label it B. Which of the following statements is true? (1 point)
The average kinetic energy of the ice in cup A is less than that in cup B.
The average kinetic energy of the ice in cup A is greater than that in cup B.
The average kinetic energy of the ice in cup A is equal to that in cup B.
The average kinetic energies of the ice in cup A and the ice in cup B are not comparable.**
19. A man relaxes in his hot tub after a long day at work. His body temperature is 98.6°F. The temperature of the water in the hot tub is 102°F. How does heat transfer? (1 point)
Heat does not transfer between his body and the water.
Heat transfers to his body from the water by conduction.
Heat transfers from his body to the water by convection.
Heat transfers from his body to the water by conduction.**
20. Use the image below to answer the following question (ruler not to scale).
An image shows two rectangular magnets positioned along a centimeter measuring stick which begins at 3 and extends past 11. To the left, labeled A, is a magnet with the red S end above the 3 mark and the blue N just past the 4 mark. To the right, labeled B, is a magnet with the blue N end just past 10 and the red S past 11.
If magnet B is moved closer to magnet A, how will magnetic potential energy be affected?
(1 point)
It will become zero.**
It will increase.
It will decrease.
It will stay the same.
21. When you turn on a television, you transform electrical energy into____. Choose all that apply. (3 points)
heat energy**
light energy
elastic potential energy
sound energy
22. Use the image below to answer the following question.
An image of an electric range burner is shown.
This device is a burner from an electric stove. It is used to transfer heat to a pot by
(1 point)
conduction.
convection.
radiation.
friction.**
23. A 60.0 N circus performer performs a high wire act 5.0 m above ground. About how much gravitational potential energy does the performer have? (1 point)
12.0 J
56.0 J**
62.0 J
300.0 J
To determine how the kinetic energy of two identical masses moving down a slope compare to each other, we need to understand the relationship between kinetic energy and mass as well as kinetic energy and velocity. The formula for kinetic energy is KE = (1/2) mv^2, where KE is the kinetic energy, m is the mass, and v is the velocity.
In this scenario, one mass is traveling twice as fast as the other mass. Let's assume that the slower mass has a velocity of v, then the faster mass would have a velocity of 2v. Since the masses are identical, the value of m would be the same for both masses.
Now, let's compare the kinetic energy of the two masses. For the slower mass, the kinetic energy would be KE = (1/2) m v^2. For the faster mass, the kinetic energy would be KE = (1/2) m (2v)^2 = (1/2) m 4v^2 = 2(mv^2).
Therefore, the kinetic energy of the faster mass is four times greater than the kinetic energy of the slower mass. So, the correct answer to the first question is "The faster object has four times as much kinetic energy as the slower object."
For the second question, we can use the formula for kinetic energy again. Given that the mass of the animal is 10.0 kg and its velocity is 3.0 m/s, we can calculate the kinetic energy using the formula KE = (1/2) mv^2. Plugging in the values, we get KE = (1/2) (10.0 kg) (3.0 m/s)^2 = (1/2) (10.0 kg) (9.0 m^2/s^2) = 45.0 J. So, the correct answer is "45.0 J."
I hope this helps! Let me know if you have any further questions.