Question 1

In a large room, a sound wave traveling from a violin produces a tone with a frequency of 264 Hz. The speed of sound in the room is 340 m/s.What is the wavelength of the sound wave from the violin?

Accepted Answer

The wavelength can be calculated using the formula: wavelength = speed of sound / frequency. So, 340 m/s divided by 264 Hz equals approximately 1.3 m.

Question 2

Which of the following statements describes the electric force betweentwo oppositely charged particles as they approach each other?

Accepted Answer

The electric force between two oppositely charged particles is attractive, and according to Coulomb's law, the magnitude of this force increases as the distance between the particles decreases. Therefore, as they approach each other, the attractive electric force increases.

Question 3

A student leaving school walks 2.5 km north and then walks 1.0 km south. What is the student's displacement?

Accepted Answer

Displacement is a vector quantity that refers to the change in position of an object. It is calculated as the final position minus the initial position. In this case, walking 2.5 km north and then 1.0 km south results in a net displacement of 1.5 km north.

Question 4

A student touches a metal sink with her finger and notices that her finger feels cold. Which of the following statements explains this observation?

Accepted Answer

Heat energy flows from the student's finger to the metal sink because the metal, being a good conductor, quickly draws heat away from the finger, making it feel cold.

Question 5

A student pushes a book across a classroom table. Which of the following statements best explains the difference between the amount of force needed to start the book moving and the amount of force needed to keep it moving?

Accepted Answer

Static friction, which must be overcome to start an object moving, is generally greater than kinetic friction, which is the frictional force encountered when an object is already in motion.

Question 6

A racecar travels at an average speed of 80 m/s in a race. The total distance of the race is 640,000 m.How long does it take the racecar to finish the race?

Accepted Answer

Time = Distance/Speed = 640,000 m / 80 m/s = 8,000 s

Question 7

Electric charges can move most easily on which of the following objects?

Accepted Answer

Metal plates conduct electricity well because metals have free electrons that can move easily, allowing electric charges to flow through them. Glass, plastic, and rubber are insulators, meaning they do not allow electric charges to move easily.

Question 8

The potential difference across a resistor is 12 V. When a current of 5 A is flowing through this resistor, what is the power used by the resistor?

Accepted Answer

The power used by the resistor can be calculated using the formula P = IV, where P is power in watts, I is current in amperes, and V is potential difference in volts. Substituting the given values, P = 5 A * 12 V = 60 W.

Question 9

The molecules in which of the following have the greatest average molecular kinetic energy?

Accepted Answer

The average molecular kinetic energy of a substance is directly related to its temperature. Water boiling in a pot on a stove is at a higher temperature than the air in a person's lungs, ice cubes in a glass of iced tea, or raindrops collecting in a puddle. Therefore, the molecules in boiling water have the greatest average molecular kinetic energy.

Question 10

A car with its horn sounding approaches a group of students. Assume the car's horn produces sound waves with a constant frequency.Which of the following statements bestexplains why the students hear a higher pitch as the car approaches than when it is stopped?

Accepted Answer

This phenomenon is explained by the Doppler effect, which states that the frequency of a wave increases for an observer towards whom the source of the wave is moving. As the car approaches, the sound waves are compressed, leading to a higher frequency heard by the students.

Question 11

Two blocks of zinc with different masses are at room temperature. Each block then absorbs the same amount of heat over 10 minutes. When the temperature of each block is then measured, block 1 is at a higher temperature than block 2. Which of the following statements most likely describes the zinc blocks?

Accepted Answer

Given the same amount of heat absorbed, the block with less mass (block 1) would experience a greater increase in temperature compared to the block with more mass (block 2), assuming the specific heat capacity of both blocks is the same.

Question 12

A rock climber weighs 550 N and is carrying a backpack that weighs 50 N. How much total work has been done after she climbs 12 m?

Accepted Answer

The total work done is calculated using the formula Work = Force x Distance. Here, the total force is the weight of the climber plus the backpack, which is 550 N + 50 N = 600 N. The distance climbed is 12 m. Therefore, the total work done is 600 N * 12 m = 7200 J.

Question 13

A 5 kg rock and a 10 kg rock are dropped from a height of 10 m. Which of the following statements describes what happens to the potential energy of the rocks?

Accepted Answer

The potential energy of an object is given by the formula PE = mgh, where m is mass, g is gravitational acceleration, and h is height. Since the 10 kg rock has more mass, it has more potential energy initially and thus loses more potential energy when it falls.

Question 14

A student is driving her car when an insect strikes her windshield. Which of the following statements best describes the forces in this situation?

Accepted Answer

According to Newton's third law of motion, for every action, there is an equal and opposite reaction. Therefore, the force with which the insect strikes the windshield is equal in magnitude and opposite in direction to the force with which the windshield strikes the insect.

Question 15

In which of the following examples is heat transferred primarily by radiation?

Accepted Answer

Radiation is the transfer of heat through electromagnetic waves, which does not require a medium to travel through. In option D, the spoon gets warm due to the infrared radiation emitted by the flame, even though it is not directly in contact with it.

Question 16

Which of the following observations demonstrates that visible light waves are electromagnetic and not mechanical?

Accepted Answer

Sunlight's ability to travel through a vacuum demonstrates that it is electromagnetic in nature. Mechanical waves require a medium to propagate, whereas electromagnetic waves do not, allowing them to travel through the vacuum of space.

Question 17

A large container of cold water is moved from a refrigerator to a table. A hot piece of metal is placed into the water. Which of the following best describes the final temperature of the metal?

Accepted Answer

The final temperature of the metal and the water will be the same because heat will transfer from the hot metal to the cold water until thermal equilibrium is reached, meaning they share the same temperature.

Question 18

Which of the following statements best explains why lightning is seen before thunder is heard?

Accepted Answer

Lightning is a form of electromagnetic radiation, which travels at the speed of light, much faster than sound, which is a mechanical wave that travels through the air at a much slower speed. This is why we see lightning before we hear thunder.

Question 19

A student is turning the handle of a generator. Another student connects a bulb to the generator. The bulb lights up. The first student continues to turn the handle of the generator at the same speed, but finds it harder to turn. Which of the following best explains this?

Accepted Answer

When the bulb is connected and lights up, the generator converts mechanical energy into electrical energy to power the bulb. This conversion process requires more mechanical energy to maintain the same speed, making it harder to turn the handle.

Question 20

Which of the following statements identifies the main difference between vector and scalar quantities?

Accepted Answer

Vectors are distinguished from scalars by having both magnitude and direction, while scalars have only magnitude.

Quiz 32: (AP) Physics: Introductory Physics