Recent questions in Force, Motion and Energy

Gravitational force
Answered

Talon Mcbride
2022-07-16

Spring Potential Energy
Answered

on2t1inf8b
2022-07-16

Can we also say $F=-\mathrm{\partial}U/\mathrm{\partial}x$, where U is the "internal" energy of the spring?

Spring Potential Energy
Answered

Libby Owens
2022-07-16

Newton's Second Law
Answered

Elsa Brewer
2022-07-16

Is there any case that acceleration $\overrightarrow{\alpha}$ is not in the direction of applied torque $\overrightarrow{\tau}$?

Newton's Second Law
Answered

logiski9s
2022-07-16

$\frac{d}{dt}{K}_{E}=\frac{d}{dt}\left(\frac{1}{2}m{v}^{2}\right)=mv\frac{dv}{dt}$

This looks really close to Newton's second law $F=ma$ but there is an extra "v" in there. Am I missing something here?

Gravitational force
Answered

kislotd
2022-07-15

Spring Potential Energy
Answered

Lorena Lester
2022-07-15

Newton's Second Law
Answered

Jayvion Caldwell
2022-07-14

Gravitational force
Answered

EnvivyEvoxys6
2022-07-14

Acceleration Due to Gravity
Answered

hornejada1c
2022-07-14

Recently, I had the first physics lab for my university physics course. This lab was fairly simple, as we were merely using a computer and a distance sensor to graph the position, velocity, and acceleration of a cart as it moved along a linear track.

One of the situations we captured data for involved starting the cart at the bottom of an inclined ramp and giving it a push upwards. As expected, it rolled up, came to a stop, and then came back down the track to its starting position. The position-vs-time graph was essentially parabolic, the velocity-vs-time graph was essentially linear, and the acceleration-vs-time graph was essentially linear. So far, so good.

At this point in the lab, the instructor pointed out that, if the data was examined closely, the acceleration of the cart was greater while the cart was traveling upwards than when the cart was traveling downwards (approximately $0.546\frac{m}{{s}^{2}}$ and $0.486\frac{m}{{s}^{2}}$, respectively), and asked us to determine why in our lab report.

Now, gravity was the only force acting upon the cart, and thus it's acceleration should be a constant, at least at the scale our experiment was conducted at, so these results are completely baffling my lab group. So far, we have proposed the following ideas, but none of them seem very plausible.

Doppler effect on the ultrasonic distance sensor

Friction

Air resistance

Human error

The first seems highly improbable, and the last three are more obfuscation and hand waving than actual theories.

Why does our experimental data show the acceleration due to gravity to change based on the direction the object is moving?

Acceleration Due to Gravity
Answered

kwisangqaquqw3
2022-05-20

I found article in which it is said that it would be incorrect to say that g is not acceleration due to gravity but local gravitational field as there is no acceleration on a block placed on a table. Please can you explain this as I am in a school and I have read only that g is acceleration due to gravity and textbooks say this too.

Acceleration Due to Gravity
Answered

kromo8hdcd
2022-05-20

When we throw an object up into the air, ignoring air resistance, etc, we define acceleration to be -9.8 m/s^2. When it goes down after its journey up, like a parabola, do we define the acceleration as 9.8 m/S^2, OR still the same as -9.8m/s^2?

I know that acceleration due to gravity is always constant, but would it be wrong to say it like the question i have above?

Newton's Second Law
Answered

lasquiyas5loaa
2022-05-20

Acceleration Due to Gravity
Answered

Kiersten Hodge
2022-05-20

Is there an online calculator to find the acceleration of gravity a massive object exerts from a specific distance? I know the effects of gravity kind of just fade out with distance but I'm asking for mass-specifics.

For example, you plug in the mass of the object and the distance from the object to get the m/s^2 (and maybe even the escape velocity)???

(I'm also thinking this would be some sort of exponential graph, like "acceleration" on the y axis and "distance" on the x axis)

Gravitational force
Answered

Tristan Meyers
2022-05-19

b. What is the gravitational force of the moon on the earth?

c. The moon’s force is what percent of the sun’s force?

Gravitational force
Answered

Jayden Mckay
2022-05-19

Gravitational force
Answered

Regina Ewing
2022-05-19

$F=-\frac{GMm}{{r}^{2}}+\frac{4{G}^{2}mM(M+m)}{{r}^{4}{c}^{2}}$

which I got from the internet since I haven't bee able to find a similar expression in any book. But i'm not sure if it's right or needs fixing.

Is the second term in the force correct?

Gravitational force
Answered

uto2rimxrs50
2022-05-19

Acceleration Due to Gravity
Answered

Jayden Mckay
2022-05-18

The University of Illinois Department of Physics article Q & A: Heavy and Light - Both Fall the Same states that the acceleration due to gravity is the same no matter the mass of the object.

However if an object, say for example the moon, were falling to the Earth, gravity would have to pull harder to speed it up the same. Would the acceleration of gravity be the same?

My question is not the same as Don't heavier objects actually fall faster … because I'm asking about acceleration of gravity, I'm asking if heavier objects would fall slower, not faster. So, wouldn't they fall slower because gravity has to pull harder?

Side note: Let's just say we also ignore the effects the other question mentions.

Acceleration Due to Gravity
Answered

dresu9dnjn
2022-05-18

I've been having some trouble in understanding acceleration due to gravity.

On earth, the acceleration due to gravity is an average of $9.80$$m/{s}^{2}$. The mass of the earth is approximately $5.972\times {10}^{24}kg$. The acceleration due to gravity on the surface of the sun is $273.7$$m/{s}^{2}$ and its mass is about $1.989\times {10}^{30}$

So

$\frac{\text{Mass of Sun}}{\text{Accelaration at Sun surface}}=\frac{\text{Mass of Earth}}{\text{Accelaration at Earth surface}}$

Why don't the above numbers equal each other? Is it because I am doing mass divided by acceleration?

When you have to provide correct answers to the questions based on motion equations physics, you must start with the examples that can help you learn more about the theory and see relevant examples. If you find it too challenging, start with the equations that help to determine the force of the motion as you estimate the energy that is being produced. It’s also helpful to compare several lab experiments to see the differences in how the concepts operate. Such an approach will help you to see the example of force and explain it both verbally and with the formulas.