Recent questions in Force, Motion and Energy

Gravitational force
Answered

vulkanere64t6
2022-05-18

Acceleration Due to Gravity
Answered

Jaiden Bowman
2022-05-18

How can we expand this following equation into 3D vector space? I learned this equation from this answer: Don't heavier objects actually fall faster because they exert their own gravity?

The answer shows how we can find time as function of distance (or single dimension) when there's force due to gravity accelerating both pieces of mass as follows:

$t=\frac{1}{\sqrt{2G({m}_{1}+{m}_{2})}}{\textstyle (}\sqrt{{r}_{i}{r}_{f}({r}_{i}-{r}_{f})}+{r}_{i}^{3/2}{\mathrm{cos}}^{-1}\sqrt{\frac{{r}_{f}}{{r}_{i}}}{\textstyle )}$

Where ${m}_{1}$ and ${m}_{2}$ are the masses of two bodies, ${r}_{i}$ is initial distance from mass to another and ${r}_{f}$ is the final distance from mass to another.

If this equation had just the force caused by gravity within it, I could easily divide it into components, and use this equation for each dimension, but as seen, this equation only has masses and distances in it.

How can I apply this kind of equation into 3d vector space, ie. get the position as 3d coordinates as function of time when initial position and velocity are known?

If this equation cannot be applied in to 3d space, then how could we derive another equation, which applies same kind of relations into 3d vector space? (I checked the answer I linked above, but it goes somewhat above my understanding, as differential equations are used.)

Gravitational force
Answered

dresu9dnjn
2022-05-18

Gravitational force
Answered

lurtzslikgtgjd
2022-05-17

J

(b) What is the magnitude of the gravitational force exerted by the Earth on the satellite?

N

(c) What force, if any, does the satellite exert on the Earth? (Enter the magnitude of the force, if there is no for

N

Acceleration Due to Gravity
Answered

sembuang711q6
2022-05-17

Consider I have a coil with a length of $5m$ and made up of copper wire with a diameter of cross-section $d$ and wrapped around an imaginary axis with radius $R$ with mass $M$

Now consider an insulator made up of a glass of mass $M$ of $5m$ of diameter $D$

If both were taken very high in the atmosphere but not away from the gravity of the earth. Then it is dropped from that point at the same level without providing any external force.

My question is that which object will move faster

Conductor. OR

Insulator

I have been taught that every object of any mass will have same acceleration due to gravity but electromagnetism course taught us that a coil will produce induction and it will slow down or speed up the coil.

Which theory is true?

Acceleration Due to Gravity
Answered

Stoyanovahvsbh
2022-05-15

1.Does the equivalence principle imply that there is some fundamental difference between acceleration due to gravity and acceleration by other means (because there is no way to 'feel' free fall acceleration for a uniform gravitational field)?

2.Does General Relativity allow you to describe the acceleration due to gravity without Newton's second law (because every other source of 'push or pull' outside the nucleus involves the electromagnetic field)?

3.Is the acceleration due to gravity a result of changes in time dilation/length contraction as opposed to an actual push or pull?\

Gravitational force
Answered

Jayla Faulkner
2022-05-14

Gravitational force
Answered

vulkanere64t6
2022-05-14

Gravitational force
Answered

Dominick Blanchard
2022-05-14

(b) Calculate the force on the baby due to Jupiter if it is at its closest to the earth, some $6.29\times {10}^{11}m$ away, showing it to be comparable to that of the father. The mass of Jupiter is about $1.90\times {10}^{27}\text{}kg$. Other objects in the room and the hospital building also exert similar gravitational forces.

Gravitational force
Answered

Jayden Mckay
2022-05-13

Gravitational force
Answered

Reese Estes
2022-05-13

Spring Potential Energy
Answered

Elle Weber
2022-05-13

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Acceleration Due to Gravity
Answered

mars6svhym
2022-05-13

Acceleration is defined as the rate of change of velocity with time. Jerk is defined as the rate of change of acceleration with time. What is the jerk due to gravity with ascent?

Acceleration Due to Gravity
Answered

ga2t1a2dan1oj
2022-05-13

Gravitational force
Answered

Jaeden Weaver
2022-05-13

${F}_{g}=m\cdot \overrightarrow{g}$

And when we're dealing with planets, we use a relation defined by the masses of two planets, distance squared and gravitational constant:

${F}_{g}=G\cdot \frac{{M}_{1}\cdot {M}_{2}}{{d}^{2}}$

I really don't get why we use just the first relation here on earth, because we're dealing with a interction between two objects... It's because our mass is irrelevant??

Zyrill Maravilla
2022-05-13

Determine the speed a2500-kg pick-up truck should attain for it to have (a) the same momentum as a 20,000-kg bus travelling at 90-kph (b) the same kinetic energy as a 1800-kg car travelling at 100-kph

Acceleration Due to Gravity
Answered

Matilda Webb
2022-05-10

I was taught in school that acceleration due to gravity is constant. But recently, when I checked Physics textbook, I noted that

$F={\displaystyle \frac{G{m}_{1}{m}_{2}}{{r}^{2}}}.$

So, as the body falls down, $r$ must be changing, so should acceleration due to gravity.

Gravitational force
Answered

fetsBedscurce4why1
2022-05-10

Gravitational force
Answered

sg101cp6vv
2022-05-10

Acceleration Due to Gravity
Answered

syaoronsangelhwc17
2022-05-10

I was asked to calculate the acceleration due to gravity on planet Mercury, if the mas of Mercury is $2,99\times {10}^{22}kg$ and its radius is $2,42\times {10}^{3}\text{}km$. The mass of the object is $10kg$ and the mass of Earth is $6\times {10}^{24}kg$ and the Radius of the Earth is $3,82\times {10}^{3}km$

This question rather puzzled me because I was not sure if my answer is correct or not but let me proceed :

$\overrightarrow{F}=m\overrightarrow{a}={F}_{g}=G\frac{{m}_{1}{m}_{2}}{{r}^{2}}$

${m}_{1}g=G\frac{{m}_{1}{m}_{2}}{{r}^{2}}$

(Note that ${m}_{2}$ = mass of mercury)

$g=\frac{(6.673\times {10}^{-11}\frac{{m}^{2}}{k{g}^{2}})(2,99\times {10}^{22}kg)}{(2,42\times {10}^{6}\text{}m{)}^{2}}$

I compute my answer to be $0.34\frac{m}{{s}^{2}}$

What really is confusing me is that when I look at my textbook, it shows me the gravitational acceleration due to gravity on mercury to be $3.59\frac{m}{{s}^{2}}$

Can someone please explain to me what the answer that I am getting is giving me? My computation was marked correct in a test but I do not understand what this value is giving me.

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.