Donya Dobbin

Western Michigan University
High School Science Teacher

Biography

I have been teaching high school math and science for 22 years. I have also taught several college level physics courses. I have a Bachelor's degree in Secondary education with a double major in Math and Physics. I have a Master's degree in Physics and a PhD in Science Education.

Education

BA Secondary Teaching
Western Michigan University
MA Physics
Western Michigan University
Phd Science Education
Western Michigan University

Educator Statistics

Numerade tutor for 6 years
739 Students Helped

Topics Covered

Mastering the Rotation of Rigid Bodies: Tips & Techniques
Explore the Fascinating Dynamics of Rotational Motion
Unlocking the Power of Magnetic Fields and Forces
Discovering the Sources of Magnetic Fields: A Comprehensive Guide
Electromagnetic Induction: Understanding the Science and Applications
Understanding Inductance: A Comprehensive Guide
Understanding Alternating Current: A Comprehensive Guide
Understanding Temperature and Heat: A Comprehensive Guide
Explore the Fascinating World of Periodic Motion - Learn More Today!

Donya's Textbook Answer Videos

08:53
Physics for Scientists and Engineers with Modern Physics

In a manufacturing process, a large, cylindrical roller is used to flatten material fed beneath it. The diameter of the roller is 1.00 m, and, while being driven into rotation around a fixed axis, its angular position is expressed as
$$\theta=2.50 t^{2}-0.600 t^{3}$$
where $\theta$ is in radians and $t$ is in seconds. (a) Find the maximum angular speed of the roller. (b) What is the maximum tangential speed of a point on the rim of the roller? (c) At what time $t$ should the driving force be removed from the roller so that the roller does not reverse its direction of rotation? (d) Through how many rotations has the roller turned between $t=0$ and the time found in part (c)?

Chapter 10: Rotation of a Rigid Object About a Fixed Axis
Donya Dobbin
02:56
Physics for Scientists and Engineers with Modern Physics

The law of atmospheres states that the number density of molecules in the atmosphere depends on height $y$ above sea level according to $$n_{V}(y)=n_{0} e^{-m_{0} g_{0} / k_{B} T}$$
where $n_{0}$ is the number density at sea level (where $y=0 ) .$ The average height of a molecule in the Earth's atmosphere is given by
$y_{\mathrm{avg}}=\frac{\int_{0}^{\infty} y n_{V}(y) d y}{\int_{0}^{\infty} n_{V}(y) d y}=\frac{\int_{0}^{\infty} y e^{-m_{0} g / k_{B} T} d y}{\int_{0}^{\infty} e^{-m_{0} g / k_{B} T} d y}$
(a) Prove that this average height is equal to $k_{\mathrm{B}} T / m_{0} g$ .
(b) Evaluate the average height, assuming the temperature is $10.0^{\circ} \mathrm{C}$ and the molecular mass is $28.9 \mathrm{u},$ both uniform throughout the atmosphere.

Chapter 21: The Kinetic Theory of Gases
Donya Dobbin
05:50
Physics for Scientists and Engineers with Modern Physics

The dimensions of a classroom are $4.20 \mathrm{m} \times 3.00 \mathrm{m} \times$ 2.50 $\mathrm{m}$ . (a) Find the number of molecules of air in the classroom at atmospheric pressure and $20.0^{\circ} \mathrm{C}$ . (b) Find the mass of this air, assuming the air consists of diatomic molecules with molar mass $28.9 \mathrm{g} / \mathrm{mol} .$ (c) Find the average kinetic energy of the molecules. (d) Find the rms molecular speed. (e) What If? Assume the molar specific heat of the air is independent of temperature. Find the change in internal energy of the air in the room as the temperature
is raised to $25.0^{\circ} \mathrm{C}$ . (f) Explain how you could convince a fellow student that your answer to part (e) is correct, even though it sounds surprising.

Chapter 21: The Kinetic Theory of Gases
Donya Dobbin
01:31
Essential University Physics

The Biot-Savart law shows that the magnetic field of a current element decreases as $1 / r^{2} .$ Could you put together a complete circuit whose field exhibits this decrease? Why or why not?

Chapter 26: Magnetism: Force and Field
Donya Dobbin
00:47
Essential University Physics

The Biot-Savart law shows that the magnetic field of a current element decreases as $1 / r^{2} .$ Could you put together a complete circuit whose field exhibits this decrease? Why or why not?

Chapter 26: Magnetism: Force and Field
Donya Dobbin
00:43
Essential University Physics

An unmagnetized piece of iron has no net magnetic dipole moment, yet it's attracted to either pole of a bar magnet. Why?

Chapter 26: Magnetism: Force and Field
Donya Dobbin
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Donya's Quick Ask Videos

0:00
Intro Stats / AP Statistics

The mean score for a test was 81.52 with a standard deviation of 9.2. The scores are normally distributed. If a person is selected at random find that the probability that his/her score was: (Round to the nearest 1000th )

a. Less than 75

b. Between 85 and 92

b. More than 95

c. If 28 students took the test, how many scored more than a 95 (round to the nearest whole number)

Donya Dobbin
03:17
Algebra

For each polynomial function, find the degree, leading term, and leading coefficient. Describe its end behavior for x → ∞ and for x → -∞. f(x) = x(4 - x^2)(2x + 1)

Donya Dobbin
06:15
Geometry

In 2012, the total student enrollment at Oxford University was 3976 undergraduate students. We also know that enrollment at Oxford grew during the decade 2010-2020 by an average of 133 students per year. This allows us to model the enrollment at Xavier over the time period 2010-2020.

(a) What function is being described here? That is, what output variable y is being described as depending on what input variable x? Describe the two variables and identify the units in which the quantities are being measured.

(b) Write down a linear equation that describes this relationship.

(c) Use your equation to estimate the student enrollment at Xavier in 2020. The actual value for the Fall 2020 semester was 4517 students; how close to this is your estimate?

In a certain city, the charge for commercial waste collection is $694.55 for 5 tons and $1098.32 for 8 tons.

(a) Find the equation of a linear function that, based on these two values, gives the cost C of waste collection in dollars as a function of the weight w in tons. Then sketch a graph of the function for weights of up to 10 tons; label your axes appropriately.

(b) What is the slope of this line? Report the number using appropriate units and interpret its meaning in the context of hauling this city's waste.

Donya Dobbin
05:37
Algebra and Trigonometry

A clock has an hour hand 14 cm long. The clock center is hanging 2 m above the ground. The clock is broken and takes 40 minutes to complete one full cycle. The time on the clock right now is 3 am.

a) Make a graph to represent the hour hand's movement in one full cycle. The graph should represent the height of the hour hand above ground as a function of minutes.
b) Write a sine function to model the movement of the hour hand.
c) After how long is the first time that the height of the hour hand will be 1.9 m above ground?
d) What is the hour hand's height after 35 minutes?

Donya Dobbin
02:19
Physics 101 Mechanics

Standing at the top of a 120-meter tall cliff, a boy throws a rock into a canyon with a horizontal velocity of 16 m/s. A. How long does it take for the rock to hit the ground? Assume that the ground at the base of the cliff is flat. B. How far from the base of the cliff does the rock hit the ground? C. What is the rock's speed just before it hits the ground?

Donya Dobbin
05:20
Geometry

Anne runs in a straight line for 1200 meters on a bearing of 39°, then turns and runs in a straight line for 2500 meters on a bearing of 146°. If she wishes to return to her starting point by running in a straight line, in which direction should she run (state as a bearing to the nearest degree)?
Solution: To return to her starting point, Anne should run on a bearing of ?? degrees, to the nearest degree.

Donya Dobbin
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