03.10.2020

The rate of change of the mass A

. 4

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Physics
Step-by-step answer
P Answered by PhD
Answers:Answer 1 (a):

According to Newton's Law of Gravitation, the Gravity Force is:

F=\frac{GMm}{{r}^{2}}     (1)

This expression can also be written as:

F=GMm{r}^{-2}     (2)

If we derive this force F respect to the distance r between the two masses:

\frac{dF}{dr}dFdr=\frac{d}{dr}(GMm{r}^{-2})dr     (3)

Taking into account GMmare constants:

\frac{dF}{dr}dFdr=-2GMm{r}^{-3}     (4)

Or

\frac{dF}{dr}dFdr=-2\frac{GMm}{{r}^{3}}     (5)

Answer 2 (a):  dF/dr represents the rate of change of the force with respect to the distance between the bodies.  

In other words, this means how much does the Gravity Force changes with the distance between the two bodies.

More precisely this change is inversely proportional to the distance elevated to the cubic exponent.

As the distance increases, the Force decreases.

Answer 3 (a):  The minus sign indicates that the bodies are being forced in the negative direction. 

This is because Gravity is an attractive force, as well as, a central conservative force.

This means it does not depend on time, and both bodies are mutually attracted to each other.

Answer 4 (b):  X=-32N/km

In the first answer we already found the decrease rate of the Gravity force respect to the distance, being its unit N/km:

\frac{dF}{dr}dFdr=-2\frac{GMm}{{r}^{3}}     (5)

We have a force that decreases with a rate 1 \frac{dF_{1}}{dr}dFdr=4N/km when r=20000km:

4N/km=-2\frac{GMm}{{(20000km)}^{3}}     (6)

Isolating -2GMm:

-2GMm=(4N/km)({(20000km)}^{3})     (7)

In addition, we have another force that decreases with a rate 2 \frac{dF_{2}}{dr}dFdr=X when r=10000km:

XN/km=-2\frac{GMm}{{(10000km)}^{3}}     (8)

Isolating -2GMm:

-2GMm=X({(10000km)}^{3})     (9)

Making (7)=(9):

(4N/km)({(20000km)}^{3})=X({(10000km)}^{3}       (10)

Then isolating X:

X=\frac{4N/km)({(20000km)}^{3}}{{(10000km)}^{3}}  

Solving and taking into account the units, we finally have:

X=-32N/km>>>>This is how fast this force changes when r=10000 km

Chemistry
Step-by-step answer
P Answered by PhD

1. As you drops a ball, its potential energy is converted into kinetic energy during its fall. It moves faster and faster as more PE is converted into KE until the ball hits the ground.

2. The conversion from PE to KE is due to the work done by gravity acceleration. As the ball is accelerated by gravity towards ground, its PE is converted to KE.

3. Total energy of the ball is conserved. Its position changes as it gets closer to the ground. Its PE decreases as its speed and hence KE increases until it hits the ground.

Chemistry
Step-by-step answer
P Answered by PhD

1. As you drops a ball, its potential energy is converted into kinetic energy during its fall. It moves faster and faster as more PE is converted into KE until the ball hits the ground.

2. The conversion from PE to KE is due to the work done by gravity acceleration. As the ball is accelerated by gravity towards ground, its PE is converted to KE.

3. Total energy of the ball is conserved. Its position changes as it gets closer to the ground. Its PE decreases as its speed and hence KE increases until it hits the ground.

Physics
Step-by-step answer
P Answered by PhD

(B) your mass is essentially unchanged but your weight is less than on Earth.

Explanation:

Well, firstly we have to explain the difference between the concepts of mass and weight:

-Mass m is the amount of matter that exists in a body, which only depends on the quantity and type of particles within it. This means mass is an intrinsic property of each body and remains the same regardless of where the body is located.  

-Weight W is a measure of the gravitational force acting on an object and is directly proportional to the product of the mass of the body by the acceleration due gravity g in that place and is mathematically expressed as:  

W=m.g  

So, according to this explanation and since the Earth and Mars have different values of acceleration due gravity (in fact, Mar's g is less than Earth's), your weight has changed, but not your mass.

Physics
Step-by-step answer
P Answered by PhD

whenever a new mass is added to spring the equilibrium state of the spring will change and then the mas will start oscillating about the new equilibrium position.

So here we can say that mass will always oscillate about its new equilibrium position if it is changed

Now in next situation it is given that

spring constant(k) = 4.9 kg/s^2

displacement of mass after suspending through spring = 20 cm

now we have the formula of spring force as

F = kx

here applied force is due to gravity so we have

mg = kx

m(9.8) = (4.9)(0.20)

m = 0.10 kg

so mass of object will be 100 g or 0.10 kg

Physics
Step-by-step answer
P Answered by PhD

(B) your mass is essentially unchanged but your weight is less than on Earth.

Explanation:

Well, firstly we have to explain the difference between the concepts of mass and weight:

-Mass m is the amount of matter that exists in a body, which only depends on the quantity and type of particles within it. This means mass is an intrinsic property of each body and remains the same regardless of where the body is located.  

-Weight W is a measure of the gravitational force acting on an object and is directly proportional to the product of the mass of the body by the acceleration due gravity g in that place and is mathematically expressed as:  

W=m.g  

So, according to this explanation and since the Earth and Mars have different values of acceleration due gravity (in fact, Mar's g is less than Earth's), your weight has changed, but not your mass.

Physics
Step-by-step answer
P Answered by PhD

whenever a new mass is added to spring the equilibrium state of the spring will change and then the mas will start oscillating about the new equilibrium position.

So here we can say that mass will always oscillate about its new equilibrium position if it is changed

Now in next situation it is given that

spring constant(k) = 4.9 kg/s^2

displacement of mass after suspending through spring = 20 cm

now we have the formula of spring force as

F = kx

here applied force is due to gravity so we have

mg = kx

m(9.8) = (4.9)(0.20)

m = 0.10 kg

so mass of object will be 100 g or 0.10 kg

Physics
Step-by-step answer
P Answered by Specialist

Option (d) is the correct answer.

Explanation:

Physical change is defined as a change in which no new product is formed, that is, there is no change in chemical composition of a substance.

For example, when ice melt then solid state of water changes into liquid state.

That is, arrangement of atoms changes and bond between the atoms do no break during a physical change.

Thus, we can conclude that the property bonds between atoms do not break; it is only the arrangement that changes explains why matter is conserved in a physical change.

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