Penny Riley

Numerade Educator

Biography

I am a current MS in Physics candidate with my research area in astrophysics. I am passionate about science and love teaching it to students!

Education

Penny has not yet added their education credentials.

Educator Statistics

Numerade tutor for 5 years
20646 Students Helped

Topics Covered

Mastering Motion: Achieving Efficiency Along a Straight Line
Mastering Newton's Laws: Tips for Applying Them Effectively
Understanding Inductance: A Comprehensive Guide
Exploring the Fascinating World of Quantum Physics
Explore the Fascinating World of Wave Optics - Unleash Its Potential
Understanding Electromagnetic Waves: A Comprehensive Guide
Electromagnetic Induction: Understanding the Science and Applications
Understanding Moment Impulse and Collisions for Better Physics
Exploring the World of Derivatives: A Comprehensive Guide
Stand Out with Differentiation Strategies | Boost Your Business
Applications of the Derivative
Understanding Electric Charge and Field: A Comprehensive Guide
Mastering the Rotation of Rigid Bodies: Tips & Techniques
Explore the Fascinating Dynamics of Rotational Motion
Understanding Equilibrium and Elasticity: A Comprehensive Guide
Discover the Power of Gravitation: Exploring the Science Behind It
Explore the Fascinating World of Periodic Motion - Learn More Today!
Exploring the Wonders of Atomic Physics: A Comprehensive Guide
Discover the Fascinating World of Nuclear Physics
Discover the Fascinating World of Particle Physics Today
Understanding Gauss's Law: A Comprehensive Guide
Unlocking the Power of Electric Potential: Exploring its Benefits
Capacitance and Dielectrics: Understanding the Basics
Understanding the First Law of Thermodynamics: Key Concepts
Understanding the Second Law of Thermodynamics: Key Principles
Exploring the Fascinating World of Mechanical Waves
Discover the Science of Sound and Hearing: Your Guide to Better Listening
Find Your Dream Job: Discover the Best Work Opportunities
Unlock the Power of Kinetic Energy: Boost Your Efficiency Today
Unlocking the Power of Potential Energy: Discover the Benefits
Save Energy and Money with Effective Conservation Techniques
Unlock the Secrets of Fluid Mechanics with Our Expert Guide
Unlocking the Power of Magnetic Fields and Forces
Understanding Chemical Equilibrium: A Comprehensive Guide
Gravity, Planetary Orbits
Master the Fundamentals of Physics: Learn Physics Basics
Understanding Alternating Current: A Comprehensive Guide
Discovering the Sources of Magnetic Fields: A Comprehensive Guide
Calculating Electrical Power: Resistance and EMF
Oscillatory Motion
Relativity
Fluid Mechanics
Understanding Reflection and Refraction of Light: A Comprehensive Guide
Motion
Motion in 2d or 3d
Understanding Temperature and Heat: A Comprehensive Guide
Unlocking the Secrets of Thermal Properties: Understanding Matter
Kinetic Theory Of Gases
Discovering the Fundamentals: Newton's Laws of Motion Explained
Condensed Matter Physics
Master Direct Current Circuits with Our Expert Guide
Momentum and Collisions
Unlocking the Power of Thermodynamics: A Comprehensive Guide
Applications of Newton’s Laws
Kinetic Theory Of Gases
Volume
Understanding Structure and Bonding: A Comprehensive Guide
Discover the Power of Gases: Benefits and Applications
Electric Forces and Electric Fields
Electric Potential and Capacitance
Current and Direct Current Circuits
Discover the Power of Liquids: Boost Your Health and Wellness Today!
Spectroscopy
Differential Equations Made Simple: Expert Tips & Resources
Mastering Multiple Integrals: Techniques and Tips
Integration
Introduction to Vector Calculus
Energy of a System
Unlock the Power of Vectors: Discover Their Limitless Possibilities
Superposition
Mechanical Waves
Maximizing Accuracy with Effective Sampling and Data Analysis
The Normal Distribution
Hypothesis Testing with One Sample: A Comprehensive Guide
Hypothesis Testing with Two Samples: A Comprehensive Guide
Hypothesis Testing: Understanding the Basics for Accurate Results
Understanding Discrete Random Variables: A Comprehensive Guide
Unlocking the Power of Periodic Table Properties | Boost Your Knowledge
Periodic Table
Chemical Reactivity
Exploring Probability Topics: From Basics to Advanced Strategies
Discover the Wonders of Chemistry: Your Introductory Guide
Acid-Base Equilibria: Understanding the Balance
The Power of Algebraic Language: Unlocking Mathematical Potential
Mastering Linear Functions: A Comprehensive Guide
How Markets Work: Understanding the Dynamics of Supply and Demand
Understanding Firm Behavior and Industry Organization

Penny's Textbook Answer Videos

01:42
Calculus: Early Transcendentals

Two balls are thrown upward from the edge of the cliff in Example 7. The first is thrown with a speed of $ 48\;ft/s $ and the other is thrown a second later with a speed of $ 24\;ft/s $. Do the balls ever pass each other?

Chapter 4: Applications of Differentiation
Section 9: Antiderivatives
Penny Riley
02:07
University Physics with Modern Physics

Two flat plates of glass with parallel faces are on a table, one plate on the other. Each plate is 11.0 cm long and has a refractive index of 1.55. A very thin sheet of metal foil is inserted under the end of the upper plate to raise it slightly at that end, in a manner similar to that discussed in Example 35.4. When you view the glass plates from above with reflected white light, you observe that, at 1.15 mm from the line where the sheets are in contact, the violet light of wavelength 400.0 nm is enhanced in this reflected light, but no visible light is enhanced closer to the line of contact. (a) How far from the line of contact will green light (of wavelength 550.0 nm) and orange light (of wavelength 600.0 nm) first be enhanced? (b) How far from the line of contact will the violet, green, and orange light again be enhanced in the reflected light? (c) How thick is the metal foil holding the ends of the plates apart?

Chapter 35: Interference
Section 5: The Michelson Interferometer
Penny Riley
02:28
University Physics with Modern Physics

A 2.20-kg hoop 1.20 m in diameter is rolling to the right without slipping on a horizontal floor at a steady 2.60 rad/s. (a) How fast is its center moving? (b) What is the total kinetic energy of the hoop? (c) Find the velocity vector of each of the following points, as viewed by a person at rest on the ground: (i) the highest point on the hoop; (ii) the lowest point on the hoop; (iii) a point on the right side of the hoop, midway between the top and the bottom. (d) Find the velocity vector for each of the points in part (c), but this time as viewed by someone moving along with the same velocity as the hoop.

Chapter 10: Dynamics of Rotational Motion
Section 3: Rigid-Body Rotation About a Moving Axis
Penny Riley
01:31
University Physics with Modern Physics

The most common isotope of uranium, $^{238}_{92}U$, has atomic mass 238.050788 u. Calculate (a) the mass defect; (b) the binding energy (in MeV); (c) the binding energy per nucleon.

Chapter 43: Nuclear Physics
Section 2: Nuclear Binding and Nuclear Structure
Penny Riley
01:24
University Physics with Modern Physics

A barrel contains a 0.120-m layer of oil floating on water that is 0.250 m deep. The density of the oil is 600 kg/m$^3$. (a) What is the gauge pressure at the oil$-$water interface? (b) What is the gauge pressure at the bottom of the barrel?

Chapter 12: Fluid Mechanics
Section 2: Pressure in a Fluid
Penny Riley
1 2 3 4 5 ... 158

Penny's Quick Ask Videos

01:12
Physics 101 Mechanics

A crate sits on a rough surface. Using a rope, a man applies a force to the crate as shown in the figure. The force is not enough to move the crate however and it remains stationary. If necessary, use Fs for the force of static friction, and Fk as the force of kinetic friction.

Penny Riley
01:08
Physics 101 Mechanics

A proton of speed v = 6 × 105 m/s enters a region of
uniform magnetic field of B = 0.5 T at an angle of
q = 30° to the magnetic field. In the region of magnetic field proton describes a helical path with radius R and pitch p (distance between loops). Find R and p.

Penny Riley
03:15
Physics 101 Mechanics

A 124 -kg balloon carrying a 22 -kg basket is descending with a constant downward velocity of 20.0 -kg stone is thrown from the basket with an initial velocity of 15.0 perpendicular to the path of the descending balloon, as measured relative to a person at rest in the basket. The person in the basket sees the stone hit the ground 6.00 s after being thrown. Assume that the balloon continues its downward descent with the same constant speed of 20.0 (a) How high was the balloon when the rock was thrown out? (b) How high is the balloon when the rock hits the ground? (c) At the instant the rock hits the ground, how far is it from the basket? (d) Just before the rock hits the ground, find its horizontal and vertical velocity components as measured by an observer (i) at rest in the basket and (ii) at rest on the ground.

Penny Riley
01:32
Physics 101 Mechanics

A light spring of unstretched length 14.2 cm is suspended vertically from a fixed point, as shown in the first figure below. A mass of weight 3.8 N is hung from the end of the spring, as shown in the second figure below. The length of the spring is now 16.3 cm. An additional force F then extends the spring so that its length becomes 17.8 cm, as shown in the third figure below. (spring obeys Hooke's law). You are required to find the magnitude of the force F.

Penny Riley
01:27
Physics 101 Mechanics

What should you do to the length of the string of a simple pendulum to (a) double its frequency; (b) double
its period; (c) double its angular frequency?

Penny Riley
01:21
Physics 103

Mary spots bill approaching the dorm at a constant rate of 2 m/s on the walkway that passes directly beneath her window, 17 m above the ground. When Bill is 120 m away from the point below her window she decided to drop an apple down to him. (a) How long should Mary wait to drop the apple if Bill is to catch it 1.75 m above the ground, and without either speeding up or slowing down? (b) How far from directly below the window is Bill when Mary releases the apple?

Penny Riley
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