You are given 2 hourglasses.one time is 4 mins another is 7.can u make exactly 9 mins?

What is 75 miles per hour (mi/h) in meters per second (m/s)? 1 mile = 1.6 km.

Sedbober [7]

Answer:33.33 m/s

Explanation: In order to calculate this conversion we have to use:

1 mile = 1.6 km and also to convert Km/h to m/s the factor is 1000/3600

then we have: 75*1.6*0.27=33.33 m/s

8 0

3 years ago

Newton's Law of Gravitation says that the magnitude F of the force exerted by a body of mass m on a body of mass M is F = GmM r2

Nookie1986 [14]

<h2>Answers:</h2>

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 $GMm$ are constants:

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

Or

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

<h2> (b) dF/dr represents the rate of change of the force with respect to the distance between the bodies. </h2><h2 />

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.

<h2>(c) The minus sign indicates that the bodies are being forced in the negative direction. </h2>

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.

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 $r=10000 km$

7 0

4 years ago

Read 2 more answers

At which point is the potential energy the greatest? At which point is kinetic energy the greatest?

notsponge [240]

Answer:

Kinetic energy is greatest at the lowest point of a roller coaster and least at the highest point.

<h2>hope it helps you </h2><h2>make me as brainlylist </h2>

3 0

4 years ago

Usually, when the temperture is increased l, what will happen to the ratevof dissolving?

pochemuha

<span>When temperature is increased, the rate of dissolving increases. The kinetic energy of the molecules of the solute and solvent molecules is high thereby increasing their contact. An example is mixing powdered sugar to the water. When you add water to the sugar, the dissolving process is slow. However, when you increase the temperature of the water by boiling it, the sugar dissolves immediately. </span>

3 0

3 years ago

Atoms with the same number of protons but different numbers of neutrons are called isomers

Ludmilka [50]

False, atoms with the the same number of protons but a differing number of neutrons is called an isotope.

An isomer is a compound that has the same atomic makeup as another, but in a different arrangement.

8 0

3 years ago