Table of contents
- 0. Math Review31m
- 1. Intro to Physics Units1h 29m
- 2. 1D Motion / Kinematics3h 56m
- Vectors, Scalars, & Displacement13m
- Average Velocity32m
- Intro to Acceleration7m
- Position-Time Graphs & Velocity26m
- Conceptual Problems with Position-Time Graphs22m
- Velocity-Time Graphs & Acceleration5m
- Calculating Displacement from Velocity-Time Graphs15m
- Conceptual Problems with Velocity-Time Graphs10m
- Calculating Change in Velocity from Acceleration-Time Graphs10m
- Graphing Position, Velocity, and Acceleration Graphs11m
- Kinematics Equations37m
- Vertical Motion and Free Fall19m
- Catch/Overtake Problems23m
- 3. Vectors2h 43m
- Review of Vectors vs. Scalars1m
- Introduction to Vectors7m
- Adding Vectors Graphically22m
- Vector Composition & Decomposition11m
- Adding Vectors by Components13m
- Trig Review24m
- Unit Vectors15m
- Introduction to Dot Product (Scalar Product)12m
- Calculating Dot Product Using Components12m
- Intro to Cross Product (Vector Product)23m
- Calculating Cross Product Using Components17m
- 4. 2D Kinematics1h 42m
- 5. Projectile Motion3h 6m
- 6. Intro to Forces (Dynamics)3h 22m
- 7. Friction, Inclines, Systems2h 44m
- 8. Centripetal Forces & Gravitation7h 26m
- Uniform Circular Motion7m
- Period and Frequency in Uniform Circular Motion20m
- Centripetal Forces15m
- Vertical Centripetal Forces10m
- Flat Curves9m
- Banked Curves10m
- Newton's Law of Gravity30m
- Gravitational Forces in 2D25m
- Acceleration Due to Gravity13m
- Satellite Motion: Intro5m
- Satellite Motion: Speed & Period35m
- Geosynchronous Orbits15m
- Overview of Kepler's Laws5m
- Kepler's First Law11m
- Kepler's Third Law16m
- Kepler's Third Law for Elliptical Orbits15m
- Gravitational Potential Energy21m
- Gravitational Potential Energy for Systems of Masses17m
- Escape Velocity21m
- Energy of Circular Orbits23m
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- Black Holes16m
- Gravitational Force Inside the Earth13m
- Mass Distribution with Calculus45m
- 9. Work & Energy1h 59m
- 10. Conservation of Energy2h 54m
- Intro to Energy Types3m
- Gravitational Potential Energy10m
- Intro to Conservation of Energy32m
- Energy with Non-Conservative Forces20m
- Springs & Elastic Potential Energy19m
- Solving Projectile Motion Using Energy13m
- Motion Along Curved Paths4m
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- Pendulum Problems13m
- Energy in Connected Objects (Systems)24m
- Force & Potential Energy18m
- 11. Momentum & Impulse3h 40m
- Intro to Momentum11m
- Intro to Impulse14m
- Impulse with Variable Forces12m
- Intro to Conservation of Momentum17m
- Push-Away Problems19m
- Types of Collisions4m
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- Adding Mass to a Moving System8m
- Collisions & Motion (Momentum & Energy)26m
- Ballistic Pendulum14m
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- Intro to Center of Mass15m
- 12. Rotational Kinematics2h 59m
- 13. Rotational Inertia & Energy7h 4m
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- Parallel Axis Theorem13m
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- Moment of Inertia & Mass Distribution10m
- Intro to Rotational Kinetic Energy16m
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- Types of Motion & Energy24m
- Conservation of Energy with Rotation35m
- Torque with Kinematic Equations56m
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- Rotational Dynamics of Rolling Motion27m
- 14. Torque & Rotational Dynamics2h 5m
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- 16. Angular Momentum3h 6m
- Opening/Closing Arms on Rotating Stool18m
- Conservation of Angular Momentum46m
- Angular Momentum & Newton's Second Law10m
- Intro to Angular Collisions15m
- Jumping Into/Out of Moving Disc23m
- Spinning on String of Variable Length20m
- Angular Collisions with Linear Motion8m
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- Angular Momentum of Objects in Linear Motion7m
- 17. Periodic Motion2h 9m
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- Velocity of Transverse Waves21m
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- Standing Wave Functions14m
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- Beats8m
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- 19. Fluid Mechanics4h 27m
- 20. Heat and Temperature3h 7m
- Temperature16m
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- Moles and Avogadro's Number14m
- Specific Heat & Temperature Changes12m
- Latent Heat & Phase Changes16m
- Intro to Calorimetry21m
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- Advanced Calorimetry: Equilibrium Temperature with Phase Changes9m
- Phase Diagrams, Triple Points and Critical Points6m
- Heat Transfer44m
- 21. Kinetic Theory of Ideal Gases1h 50m
- 22. The First Law of Thermodynamics1h 26m
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- 24. Electric Force & Field; Gauss' Law3h 42m
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- 26. Capacitors & Dielectrics2h 2m
- 27. Resistors & DC Circuits3h 8m
- 28. Magnetic Fields and Forces2h 23m
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- Magnetic Field Produced by Moving Charges10m
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- Magnetic Force Between Parallel Currents12m
- Magnetic Force Between Two Moving Charges9m
- Magnetic Field Produced by Loops andSolenoids42m
- Toroidal Solenoids aka Toroids12m
- Biot-Savart Law (Calculus)18m
- Ampere's Law (Calculus)17m
- 30. Induction and Inductance3h 38m
- 31. Alternating Current2h 37m
- Alternating Voltages and Currents18m
- RMS Current and Voltage9m
- Phasors20m
- Resistors in AC Circuits9m
- Phasors for Resistors7m
- Capacitors in AC Circuits16m
- Phasors for Capacitors8m
- Inductors in AC Circuits13m
- Phasors for Inductors7m
- Impedance in AC Circuits18m
- Series LRC Circuits11m
- Resonance in Series LRC Circuits10m
- Power in AC Circuits5m
- 32. Electromagnetic Waves2h 14m
- 33. Geometric Optics2h 57m
- 34. Wave Optics1h 15m
- 35. Special Relativity2h 10m
8. Centripetal Forces & Gravitation
Acceleration Due to Gravity
Problem 12b
Textbook Question
The mass of Venus is 81.5% that of the earth, and its radius is 94.9% that of the earth. If a rock weighs 75.0 N on earth, what would it weigh at the surface of Venus?

1
First, understand that weight is the force exerted by gravity on an object. It is calculated using the formula: , where is the weight, is the mass of the object, and is the acceleration due to gravity.
Next, calculate the gravitational acceleration on Venus using the formula: , where is the gravitational constant, is the mass of Venus, and is the radius of Venus.
Since the mass of Venus is 81.5% that of Earth, express this as , where is the mass of Earth.
Similarly, the radius of Venus is 94.9% that of Earth, expressed as , where is the radius of Earth.
Finally, substitute these values into the gravitational acceleration formula to find for Venus, and then use the weight formula to calculate the weight of the rock on Venus, knowing its mass from its weight on Earth.

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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Gravitational Force
Gravitational force is the attractive force between two masses. On a planetary surface, it is calculated using the formula F = mg, where F is the force (weight), m is the mass of the object, and g is the acceleration due to gravity. The weight of an object varies depending on the gravitational pull of the planet it is on.
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Acceleration Due to Gravity
The acceleration due to gravity (g) on a planet's surface is determined by the planet's mass and radius. It is calculated using the formula g = G * (M/R^2), where G is the gravitational constant, M is the planet's mass, and R is its radius. This value affects how much an object weighs on that planet.
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Proportionality and Ratios
Proportionality and ratios are mathematical tools used to compare quantities. In this context, they help determine how changes in mass and radius affect gravitational force. By comparing Venus's mass and radius to Earth's, we can calculate the change in gravitational acceleration and thus the weight of an object on Venus.
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