Motion & Forces
A student leaving school walks 2.5 km north and then walks 1.0 km south. What is the student’s displacement?
A. 1.0 km south
B. 1.5 km north
C. 2.5 km north
D. 3.5 km south
B. 1.5 km north
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?
A. 0.004 m
B. 0.80 m
C. 1.3 m
D. 2.6 m
C. 1.3 m
Electric charges can move most easily on which of the following objects?
A. glass tubes
B. metal plates
C. plastic cups
D. rubber tires
B. metal plates
A student touches a metal sink with her finger and notices that her finger feels cold. Which of the following statements explains this observation?
A. Heat energy flows from the student’s finger to the metal sink.
B. Heat energy flows from the metal sink to the student’s finger.
C. The student’s finger was originally at the same temperature as the sink.
D. The student’s finger was originally at a lower temperature than the sink.
A. Heat energy flows from the student’s finger to the metal sink.
A meteoroid with a mass of 1,000 kg enters Earth’s atmosphere with a velocity of 4,400 m/s. What is the magnitude of the meteoroid’s momentum at that instant?
A. 44 kg • m/s
B. 2,200,000 kg • m/s
C. 4,400,000 kg • m/s
D. 9,680,000,000 kg • m/s
C. 4,400,000 kg • m/s
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?
A. Less force is needed to start the book moving, because there is less friction than when it is already moving.
B. Less force is needed to start the book moving, because there is less potential energy in the table than in the book.
C. More force is needed to start the book moving, because there is more potential energy in the table than in the book.
D. More force is needed to start the book moving, because there is more friction than when it is already moving.
D. More force is needed to start the book moving, because there is more friction than when it is already moving.
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 best explains why the students hear a higher pitch as the car approaches than when it is stopped?
A. The sound waves increase in speed as the car approaches the students.
B. The sound waves decrease in speed as the car approaches the students.
C. The sound waves are heard at a lower frequency as the car approaches the students.
D. The sound waves are heard at a higher frequency as the car approaches the students.
D. The sound waves are heard at a higher frequency as the car approaches the students.
Which of the following statements describes the electric force between two oppositely charged particles as they approach each other?
A. The attractive electric force increases.
B. The electric force becomes repulsive.
C. The magnitude of the electric force decreases.
D. The repulsive electric force becomes attractive.
A. The attractive electric force increases.
The molecules in which of the following have the greatest average molecular kinetic energy?
A. air in a person’s lungs
B. ice cubes in a glass of iced tea
C. raindrops collecting in a puddle
D. water boiling in a pot on a stove
D. water boiling in a pot on a stove
The momentum of an object in space is
A. dependent on its mass.
B. independent of its inertia.
C. independent of its velocity.
D. dependent on its potential energy.
A. dependent on its mass.
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 race car to finish the race?
A. 800 s
B. 8,000 s
C. 6,400,000 s
D. 51,200,000 s
B. 8,000 s
Which of the following statements best explains why lightning is seen before thunder is heard?
A. Electromagnetic waves travel faster than mechanical waves in air.
B. Electromagnetic waves have a higher frequency than mechanical waves.
C. Electromagnetic waves experience less interference than mechanical waves.
D. Electromagnetic waves form faster than mechanical waves during a thunderstorm.
A. Electromagnetic waves travel faster than mechanical waves in air.
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?
A. 2.4 W
B. 60 W
C. 300 W
D. 1500 W
B. 60 W
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?
A. The mass of block 1 is less than the mass of block 2.
B. The mass of block 1 is greater than the mass of block 2.
C. The specific heat of block 1 is less than the specific heat of block 2.
D. The specific heat of block 1 is greater than the specific heat of block 2.
A. The mass of block 1 is less than the mass of block 2.
Which of the following statements best describes the force of Earth’s gravity on a rocket moving upward?
A. The gravitational force is constant for all altitudes.
B. The gravitational force is weaker when the rocket is higher.
C. The gravitational force is stronger when the rocket is higher.
D. The gravitational force is zero when the altitude is greater than 10,000 miles.
B. The gravitational force is weaker when the rocket is higher.
A student is driving her car when an insect strikes her windshield. Which of the following statements best describes the forces in this situation?
A. The insect strikes the windshield with the same force as the windshield strikes the insect.
B. The insect strikes the windshield with a force, and the windshield exerts no force on the insect.
C. The insect exerts no force on the windshield, and the windshield strikes the insect with a large force.
D. The insect strikes the windshield with a small force, and the windshield strikes the insect with a large force.
A. The insect strikes the windshield with the same force as the windshield strikes the insect.
Which of the following properties is the same for all electromagnetic waves in a vacuum?
A. amplitude
B. frequency
C. speed
D. wavelength
C. speed
Which of the following observations demonstrates that visible light waves are electromagnetic and not mechanical?
A. Sunlight can pass through gas.
B. Sunlight can pass through solids.
C. Sunlight can pass through liquids.
D. Sunlight can pass through a vacuum.
D. Sunlight can pass through a vacuum.
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?
A. 50 J
B. 600 J
C. 6000 J
D. 7200 J
D. 7200 J
Which of the following statements describes a result of Earth’s gravitational pull on the Moon?
A. The Moon has craters.
B. The Moon orbits around Earth.
C. The Moon lacks an atmosphere.
D. The Moon has less gravity than Earth.
B. The Moon orbits around Earth.
Which of the following statements identifies the main difference between vector and scalar quantities?
A. Only vectors have direction.
B. Only scalars have magnitude.
C. Only scalars have units associated with them.
D. Only vectors have units associated with them.
A. Only vectors have direction.
The source of a sound is moving away from an observer who is standing still. How do the sound waves received by the observer compare with those emitted by the source?
A. They are heard as having a greater velocity.
B. They are heard as having a higher frequency.
C. They are heard as having a lower frequency.
D. They are heard as having a smaller wavelength.
C. They are heard as having a lower frequency.
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?
A. Less mechanical energy is required when the bulb is lit.
B. More energy is put into the generator when the bulb is lit.
C. Less mechanical energy is required the longer the generator is turned and the bulb is lit.
D. The energy requirement of the generator is the same at any speed whether or not the bulb is lit.
B. More energy is put into the generator when the bulb is lit.
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?
A. Neither rock loses potential energy because no work is done on the rocks.
B. Both rocks lose the same amount of potential energy because they fall from the same height.
C. The 10 kg rock loses more potential energy than the 5 kg rock because the 10 kg rock falls faster.
D. The 10 kg rock loses more potential energy than the 5 kg rock because the 10 kg rock has more mass.
D. The 10 kg rock loses more potential energy than the 5 kg rock because the 10 kg rock has more mass.
Which of the following has the greatest momentum?
A. a 60 kg deer moving west at a speed of 16.4 m/s
B. a 6300 kg elephant moving east at a speed of 0.11 m/s
C. a 0.42 kg soccer ball moving downfield at a speed of 12 m/s
D. a 0.03 kg arrow moving toward a target at a speed of 150 m/s
A. a 60 kg deer moving west at a speed of 16.4 m/s