General Physics 1 - Torque and Angular Momentum

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Questions and Answers

What are nodes in standing waves on strings?

Points where the wave disturbance is zero and the string does not move (correct)

Areas of destructive interference with decreased amplitude

Locations of increasing frequency in the wave

Points of maximum amplitude where the string moves

How is a sonic boom created?

Through destructive interference of sound waves

By a sudden change in sound frequency

From simultaneous similar sound waves arriving together (correct)

By an object moving slower than sound

What is the phenomenon called that describes the apparent change in frequency of sound due to the relative motion between the source and the observer?

Sonic transition

Frequency modulation

Doppler effect (correct)

Wave interference

In Doppler radar, which application utilizes the Doppler shift?

Tracking the movement of storm clouds Signup and view all the answers

What is the unit of measurement for torque?

Newton · meter Signup and view all the answers

What scenario leads to the creation of a bow wake?

Movement of the wave source faster than its wave propagation speed Signup and view all the answers

When is the torque considered positive?

When it produces counterclockwise rotation Signup and view all the answers

What happens inside the cone of a sonic boom?

Sound intensity is significantly lower Signup and view all the answers

What is the correct equation to calculate torque?

τ = rFsinθ Signup and view all the answers

Which of the following represents the situation where the net external force is zero?

Net F = 0 Signup and view all the answers

How can the Doppler shift in ultrasound be effectively used?

To measure blood velocity Signup and view all the answers

In the context of torque, what does the angle θ represent?

The angle between the force and the moment arm Signup and view all the answers

What is created by two sonic booms from an aircraft?

One boom from the nose and one from the tail Signup and view all the answers

Which condition is NOT necessary to achieve static equilibrium in a system?

The net external force must be non-zero Signup and view all the answers

What phenomenon occurs when the direction of spin is changed but not its speed?

Precession Signup and view all the answers

Which statement about torque and force is incorrect?

Torque can speed up or slow down an object's rotation. Signup and view all the answers

What relationship represents the speed of sound in terms of frequency and wavelength?

vw = fλ Signup and view all the answers

What happens to the eardrum in response to sound waves?

It vibrates due to sound wave compressions and rarefactions. Signup and view all the answers

How does the speed of sound vary with frequency in open air?

It is nearly independent of frequency. Signup and view all the answers

If high-frequency sounds traveled faster than low-frequency sounds, what would be the likely effect?

Low-pitch instruments would lag behind high-pitch instruments. Signup and view all the answers

What occurs when two waves of the same amplitude and wavelength interfere with each other?

They alternate between constructive and destructive interference. Signup and view all the answers

What is a characteristic of standing waves found on strings of musical instruments?

They are caused by wave reflections from the ends of the string. Signup and view all the answers

What effect does wavelength have as frequency increases for sound waves in a constant medium?

Wavelength decreases. Signup and view all the answers

What is the primary factor that leads to a net force on the eardrum when sound waves reach it?

Atmospheric pressure behind the eardrum differs from sound wave pressure. Signup and view all the answers

What happens to the water level in a glass when ice cubes are added to it?

The water spills over the edge. Signup and view all the answers

According to Archimedes' principle, what determines whether an object will float or sink?

The weight of the object compared to the weight of the water it displaces. Signup and view all the answers

Which principle is described by stating that the buoyant force on an object is equal to the weight of the fluid it displaces?

Archimedes' Principle Signup and view all the answers

What does Bernoulli’s equation primarily consider in fluid mechanics?

Pressure and gravitational forces. Signup and view all the answers

When a solid object is placed in a fluid, what effect does it have on the fluid's surface?

It displaces an amount of fluid equal to its own weight. Signup and view all the answers

How can Archimedes' principle be applied in real-world scenarios?

To determine the volumes of irregular objects. Signup and view all the answers

What does the upthrust or buoyant force acting on an object in a fluid depend on?

The density of the fluid and the volume of fluid displaced. Signup and view all the answers

In what way do hot air balloons utilize Archimedes' principle?

By displacing air with heated air to rise. Signup and view all the answers

What is angular acceleration a measure of?

The rate of change of angular velocity Signup and view all the answers

What happens to angular acceleration when angular velocity decreases?

It is negative Signup and view all the answers

What is the relationship between angular velocity and linear velocity in circular motion?

Linear velocity equals radius times angular velocity Signup and view all the answers

How is uniform circular motion characterized?

Constant angular velocity at a uniform radius Signup and view all the answers

What defines a positive angular acceleration?

An increase in angular velocity Signup and view all the answers

When an ice skater pulls her arms in to increase her spin, what phenomenon is occurring?

Decrease in moment of inertia Signup and view all the answers

Which of the following describes angular velocity?

The time rate of change of angle Signup and view all the answers

In which scenario is angular acceleration present?

A merry-go-round starting from rest Signup and view all the answers

What does the first law of thermodynamics state?

Energy can be transferred or changed, but not created or destroyed. Signup and view all the answers

What does the second law of thermodynamics describe?

Heat always flows from a body at a higher temperature to a body at a lower temperature. Signup and view all the answers

What is the significance of the third law of thermodynamics?

It defines entropy at absolute zero. Signup and view all the answers

In the zeroth law of thermodynamics, what condition indicates thermal equilibrium?

A thermometer can measure the same temperature in both systems. Signup and view all the answers

Which theory was predominant before the establishment of thermodynamics?

Caloric Theory Signup and view all the answers

What can be inferred about a system's entropy as it approaches absolute zero?

Entropy is well-defined and corresponds to the degeneracy of the ground state. Signup and view all the answers

According to thermodynamics, heat energy is categorized under which type of energy?

Thermal energy Signup and view all the answers

In the context of a heat engine, which law is essential for understanding the flow of heat?

Second Law of Thermodynamics Signup and view all the answers

Study Notes

General Physics 1 - Second Quarter

Week 1: Torque and Angular Momentum
- Torque is derived from the Latin word torquere, meaning "to twist."
- Torque is the turning force, and it's a vector quantity.
- The unit of measurement for torque is Newton-meter (Nm).
- Torque can be viewed as having two parts: one in the direction of the rotation axis, and the other perpendicular to the axis.
- Torque (τ) = Force (F) × Moment arm (l) = rFsinθ, where r is the perpendicular distance, F is the force, and θ is the angle between r and F.
- Torque is positive when the force tends to produce counterclockwise rotation and negative for clockwise rotation.
- Torque does not change the speed of rotation, but it changes the direction of spin (precession).
Engagement (Page 2)
- Force is most effective in producing torque when exerted perpendicular to the wrench.
- Torque is calculated as force multiplied by the lever arm.
- Example problem: calculating the force needed to achieve a specific torque when tightening a spark plug. Example torque problem: calculating the force needed to apply torque to open a door.
- More examples of calculating torque in different scenarios.
Assimilation (Page 3)
- Equilibrium requires net external force and net external torque to be zero, for rotational equilibrium.
- Torque is the rotational equivalent of force and is a measure of how effective a force is in changing or accelerating rotation.
- The second condition for equilibrium is that the net external torque on a system must be zero.
- Torques in opposite directions are assigned opposite signs (counterclockwise positive, clockwise negative).
Week 2: Rotational Kinematics & Moment of Inertia
- Torque causes rotation.
- Angular acceleration relates to the rate of change of angular velocity and is the rotational analog of linear acceleration.
- Angular velocity (ω) = Δθ/Δt, where Δθ is the change in angle and Δt is the change in time.
- Linear velocity (v) = rω, where r is the radius of curvature.
- Angular acceleration (α) = Δω/Δt.
- The moment of inertia (I) is a measure of an object's resistance to changes in its rotation.
- Moment of inertia is the rotational equivalent of mass.
- It depends on mass and axis of rotation.
Calculating Angular Acceleration and Deceleration of Bike Wheel (Page 5)
- The problem provides data on initial and final angular velocity and time.
- The equation for angular acceleration formula (α = Δω/Δt) is used to calculate the angular velocity. (Δω: change in angular velocity, Δt: change in time)
- Units are converted to standard units for angular acceleration (rad/s²).
Moment of Inertia (Page 6)
- Object's resistance to changes in rotation; calculated as sum of masses at different distances from axis of rotation.
- The total moment of inertia depends on mass and the axis of rotation selected.
- A rotating mass possesses kinetic energy, dependent on moment of inertia and angular velocity.
Assessment (Page 7)
- Imagine a merry-go-round. Compare the kinetic energy of two kids sitting at different distances.
Week 3-4: Newton's Law of Universal Gravitation & Kepler's Laws of Planetary Motion
- Newton compared the acceleration of the moon to that of objects on Earth.
- Objects with greater mass attract each other gravitationally with more force.
- Universal Law of Gravitation explains this.
- F = Gm1m2/r^2, where G is the universal gravitational constant, m1 and m2 are masses, and r is the distance between their centers.
- Gravitational force is directly proportional to the masses of the interacting objects but inversely proportional to the square of the distance between their centers.
Engagement and Assessment (Page 9, 10)
- Gravitational force between objects is equal and opposite. Objects with greater mass experience greater acceleration when attracting.
- Heavier objects experience larger gravitational attractive, gravitational interaction between objects.
- Gravitational force between objects is equal and opposite, regardless if one is a heavier object or not. Heavier objects do experience greater acceleration if experiencing forces of equal magnitude to one another. If both objects experience and have the same forces, however, the objects will move and accelerate at the same rate.
- Doubling the distance between two objects reduces the gravitational force to 1/4 of its original value.
- Kepler's three laws of planetary motion were developed to describe the mechanics of planetary motion, describing elliptical motion, equal area in equal time, and ratio of the orbital periods and orbital radii.
Week 5: Periodic Motion and Waves
- Periodic motion is motion that repeats at regular intervals.
- Mechanical waves require a medium to propagate and can be transverse or longitudinal.
- Defining frequency and periods.
Week 6: Sound
- Sound waves cannot travel through a vacuum.
- Relationship between speed of sound (v_w), frequency (f), and wavelength (λ): v_w= fλ.
- Standing waves occur when waves reflect from the ends of a string/medium which creates nodes and antinodes.
- Doppler Effect: Apparent change in frequency of a wave, like sound, due to relative motion between source and observer.
- Inverse Square Law: Sound intensity decreases with the square of the distance from the source.
Week 7: Specific Gravity, Pressure, and Buoyancy
- Matter exists as solid, liquid, or gas, and is often measured by density.
- Density (ρ) = Mass (m) / Volume (V).
- Specific gravity is the ratio of the density of a substance to the density of water at a specific temperature (usually 20°C).
- Pascal's Principle: Pressure applied to an enclosed fluid is transmitted equally in all directions.
- Bernoulli's Principle: As the speed of a fluid increases, its pressure decreases.
- Archimedes' Principle: The buoyant force on an object in a fluid is equal to the weight of the fluid displaced by the object.
Week 8-9: Laws of Thermodynamics
- Thermodynamics deals with heat energy and its relationships to other forms of energy.
- The First Law of Thermodynamics is the principle of conservation of energy, as applied to thermal systems.
- Entropy is a measure of the disorder of a system.
- The Second Law of Thermodynamics describes the direction of energy flow and establishes the concept of entropy. The entropy of an isolated system can increase, but it never decrease.
- The Third Law of Thermodynamics describes the behavior of systems as their temperature approaches absolute zero. The entropy of a system approaches a constant value as the temperature approaches zero.
Assessment Questions (Various Weeks)
- Includes a variety of conceptual and calculation questions on topics covered in the materials.

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Test your knowledge on Torque and Angular Momentum in General Physics 1. This quiz covers key concepts such as the definition of torque, its calculation, and its effects on rotational motion. Dive into the intricacies of angular momentum and understand how forces interact to create rotational effects.