Deck 36: Praxis II Physics Content Knowledge

Question 1

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.

Answer 1

More force is needed to start the book moving, because there is more friction than when it is already moving.

Question 2

A cart at the top of a hill is released and rolls down the hill. Which of the following describes the energy of the cart just as it reaches the bottom of the hill?

A)The cart has no energy.
B)The cart has maximum kinetic energy.
C)The cart has maximum gravitational potential energy.
D)The cart has equal gravitational potential and kinetic energy.

Answer 2

The cart has maximum kinetic energy.

Question 3

To make ice, water must irst be cooled. The speciic heat of water is 4,186 J/kg • °C.
Approximately how much heat must be removed from 0.50 kg of water to change its temperature from 24°C to 5°C?

A)0 J
B)19,900 J
C)39,800 J
D)79,500 J

Answer 3

39,800 J

Question 4

Which of the following is possible due to longitudinal waves?

A)seeing the color red
B)getting a tan at the beach
C)hearing the sound of the ocean
D)riding a wave on a surfboard

Question 5

A heated rock is placed in a container of water that is cooler than room temperature. Which of the following statements best describes what happens?

A)Cold is removed from the container of water until the rock, the container, and the water all reach the same final temperature.
B)The heated rock loses heat to the container of water until the rock, the container, and the water all reach the same final temperature.
C)The heated rock loses heat to the container of water until the rock, the container, and the water each reach a different final temperature.
D)Cold is removed from the container of water until the rock, the container, and the water each reach a final temperature lower than their original temperatures.

Question 6

How much power is required to carry a 35 N package a vertical distance of 18 m if the work on the package is accomplished in 30 s?

A)16 W
B)21 W
C)58 W
D)630 W

Question 7

The power of a toaster can be determined if which of the following values are known?

A)the dimensions of the toaster
B)the resistance of the toaster's insulation
C)the voltage applied to the toaster and the toaster's temperature
D)the current through the circuit and the voltage applied to the toaster

Question 8

When one end of a short metal bar is heated, the opposite end will eventually become hot. Which of the following processes transfers the heat through the bar?

A)condensation
B)conduction
C)convection
D)radiation

Question 9

Why does a plastic rod have a negative charge after being rubbed with a piece of fur?

A)The fur gives up protons to the rod.
B)The rod gives up electrons to the air.
C)The fur gains protons from the rod.
D)The rod gains electrons from the fur.

Question 10

The motor of one car is more powerful than the motor of another car. Which of the following must be true of the more powerful motor?

A)It can do work more quickly.
B)It can operate for a longer time.
C)It can burn fuel more eficiently.
D)It can store more potential energy.

Question 11

Which of the following is a main factor that affects the speed of a wave?

A)the pitch of sound
B)the loudness of sound
C)the amplitude of the wave
D)the properties of the medium

Question 12

A 600 g basketball, a 57 g tennis ball, a 46 g golf ball, and a 2.7 g table tennis ball are moving with the same velocity. Which ball has the greatest momentum?

A)golf ball
B)basketball
C)tennis ball
D)table tennis ball

Question 13

What is the mass of an object weighing 63 N on Earth?

A)0)1 kg
B)6)3 kg
C)73 kg
D)617 kg

Question 14

Two identical beakers each contain 250 mL of water. The temperature of the water is 85°C in one beaker and 15°C in the other beaker. A drop of red food coloring is placed in each beaker at the same time. During the irst minute, which of the following is most likely to happen?

A)The food coloring will spread out faster in the 85°C water than in the 15°C water.
B)The food coloring will form a layer at the top of each beaker since it does not mix with water
C)The food coloring will spread only halfway through the water in each beaker due to convection currents.
D)The food coloring will settle faster at the bottom of the beaker containing 85°C water than at the bottom of the beaker containing 15°C water.

Question 15

Two oppositely charged objects are separated by a small distance. The objects are then moved three times farther apart from each other. Which of the following statements best describes what happens to the electrical force between the objects?

A)The force of attraction increases.
B)The force of attraction decreases.
C)The force of attraction becomes zero.
D)The force of attraction stays the same.

Question 16

Which of the following conditions results in the buildup of static charge on an object?

A)when neutrons outnumber electrons
B)when there are more protons than neutrons
C)when there are more electrons than protons
D)when all neutrons have been removed from the object

Question 17

Which of the following properties is the same for all electromagnetic waves in a vacuum?

A)amplitude
B)frequency
C)speed
D)wavelength

Question 18

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.

Question 19

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?

A)higher than the final temperature of the water
B)the same as the final temperature of the water
C)lower than the initial temperature of the water
D)the same as the initial temperature of the water

Question 20

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?

A)800 s
B)8,000 s
C)6,400,000 s
D)51,200,000 s

Question 21

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.

Question 22

Radio waves, visible light, and x-rays are examples of electromagnetic waves that always differ from each other in

A)amplitude.
B)intensity.
C)temperature.
D)wavelength.

Question 23

Which of the following observations is a result of the Doppler effect?

A)Noise from across a lake is louder at night than during the day
B)A person walking notices that the pitch of a car's engine decreases as the car passes by.
C)Beats are produced when two tuning forks with different frequencies are heard together.
D)A person hears the sound from a radio more clearly in certain areas of a room than in others.

Question 24

Which of the following statements best explains why drops of liquid form on the outside of a glass of ice water on a hot day?

A)Water molecules in the air are attracted to the surface of the glass.
B)Water molecules in the ice water lose energy as they transfer heat to the air.
C)Water molecules in the air lose energy as they transfer heat to the cold glass.
D)Water molecules in the ice water move through the glass pores to the outside of the glass.

Question 25

Two students are standing next to each other on a level field. One of the students throws a table tennis ball forward toward a line 2.0 m away. At the same time, the second student throws a bowling ball in the same direction. Both balls take the same time to travel the 2.0 m.
Only the second student feels a noticeable backward push when she throws her ball.
Which of the following statements explains why only the second student feels a noticeable backward push?

A)The bowling ball exerts a much larger reaction force.
B)The bowling ball undergoes a much larger acceleration
C)The bowling ball requires more force to overcome gravity.
D)The bowling ball converts more inertia into kinetic energy

Question 26

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.

Question 27

Two full 2 L bottles of water are placed on a table. Bottle 1 was just removed from a refrigerator; bottle 2 is at room temperature.
Which of the following statements describes the average molecular kinetic energy and the speed of the molecules in each bottle?

A)Bottle 1 has the same average molecular kinetic energy as bottle 2, and the molecules have the same average speed in both bottles.
B)Bottle 1 has a smaller average molecular kinetic energy than bottle 2, and the molecules have the same average speed in both bottles.
C)Bottle 1 has a smaller average molecular kinetic energy than bottle 2, and the molecules have a slower average speed in bottle 1 than in bottle 2.
D)Bottle 1 has a larger average molecular kinetic energy than bottle 2, and the molecules have a slower average speed in bottle 1 than in bottle 2.

Question 28

A student swings a bat horizontally, making contact with a ball thrown to her. The ball leaves the bat, and the bat continues moving through the rest ofthe swing.
Which of the following statements describes the change in energy ecessary to do work on the ball?

A)All the kinetic energy of the bat is converted to work.
B)All the potential energy of the bat is converted to work.
C)Some of the kinetic energy of the bat is converted to work.
D)Some of the potential energy of the bat is converted to work.

Question 29

What is the mathematical product of mass and velocity of a moving object?

A)Deceleration
B)Acceleration
C)Momentum
D)Speed

Question 30

What is a lever?

A)A rigid bar that revolves around a fixed point
B)The pivot point between force and resistance
C)The distance from the axis to the resistance
D)A force that overcomes gravity around the base of support

Question 31

How many meters is equivalent to 36.2 inches?

A)1435 meters
B)1)0 meters
C)0)72 meters
D)0)92 meters

Question 32

What is 81kg in pounds?

A)23 pounds
B)36.8 pounds
C)178.2 pounds
D)190 pounds