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4 years ago

Which forms first: protoplanets or planetesimals?

1 answer:

6 0

A planetesimal is small bodies from which a planet originated in the early stages of formation of the solar system. Protoplanets are when planetesimals join together through collisions and through the force of gravity to form larger bodies.

Therefore, planetesimals are formed first.

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Which best describes the law of conservation of mass?

Sedbober [7]

<span>D: The mass of the reactants and products is equal and is not dependent on the physical state of the substances.

Hope it helps!
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7 0

3 years ago

Read 2 more answers

A 100-lb load hangs from three cables of equal length that are anchored at the points (minus4,0,0), (2,2 StartRoot 3 EndRoo

Anarel [89]

Answer:

$\vec{F}_{cable_1} = (-19.245 \ lbf ,0, 33.333 \ lbf)$
$\vec{F}_{cable_2} = (9.622 \ lbf , 13.608 \ lbf ,33.333 \ lbf)$
$\vec{F}_{cable_3} = (9.622 \ lbf , -13.608 \ lbf ,33.333 \ lbf)$

Explanation:

The mass of the load is

$m_{load} = 100 \ lb$

As the mass hangs, the cables must be tight, so, we can obtain the vector parallel to the cable as:

$\vec{r}_{cable} = \vec{r}_{anchored} - \vec{r}_{load}$

where $\vec{r}_{load}$ is the position of the load and $\vec{r}_{anchored}$ is the point where the cable is anchored.

So, for our cables

$\vec{r}_{cable_1} = (-4,0,0) - (0,0,-4\sqrt{3})=(-4,0,4\sqrt{3})$

$\vec{r}_{cable_2} = (2,2\sqrt{3},0) - (0,0,-4\sqrt{3})=(2,2\sqrt{2},4\sqrt{3})$

$\vec{r}_{cable_3} = (2,-2\sqrt{3},0) - (0,0,-4\sqrt{3})=(2,-2\sqrt{2},4\sqrt{3})$

We know that the forces must be in this directions, so we can write

$\vec{F}_i=k_i \vec{r}_{cable_i}$

We also know, as the system is in equilibrium, the sum of the forces must be zero:

$\vec{F}_{cable_1}+\vec{F}_{cable_2}+\vec{F}_{cable_3}+\vec{W}=0$

where $\vec{W}$ is the weight,

$\vec{W} = (0,0,-100 \ lbf)$

So, we get:

$k_1 (-4,0,4\sqrt{3}) + k_2 (2,2\sqrt{2},4\sqrt{3}) + k_3 (2,-2\sqrt{2},4\sqrt{3}) + (0,0,-100 \ lbf) = (0,0,0)$

This gives us the following equations:

$-4 \ k_1 + 2 \ k_2 + 2 \ k_3 = 0$
$2\sqrt{2} \ k_2 -2\sqrt{2} \ k_3 = 0$
$4\sqrt{3} \ k_1 + 4\sqrt{3} \ k_2 + 4\sqrt{3} \ k_3 -100 \ lbf = 0$

From equation [2] is clear that $k_2 = k_3$ , we can see that

$2\sqrt{2} \ k_2 = 2\sqrt{2} \ k_3$

$\frac{2\sqrt{2} \ k_2}{2\sqrt{2} } = \frac{2\sqrt{2} \ k_3}{2\sqrt{2} }$

$k_2 = k_3$

Now, putting this in equation [1]

$-4 \ k_1 + 2 \ k_2 + 2 \ k_3 = -4 \ k_1 + 2 \ k_3 + 2 \ k_3 = -4 \ k_1 + 4 \ k_3 = 0$

$4 \ k_1 = 4 \ k_3$

$\ k_1 = \ k_3$

Taking this result to the equation [3]

$4\sqrt{3} \ k_1 + 4\sqrt{3} \ k_2 + 4\sqrt{3} \ k_3 -100 \ lbf = 0$

$4\sqrt{3} \ k_3 + 4\sqrt{3} \ k_3 + 4\sqrt{3} \ k_3 = 100 \ lbf$

$3 * (4\sqrt{3} \ k_3) = 100 \ lbf$

$k_3 = \frac{100 \ lbf}{ 12 \sqrt{3}}$

$k_1 = k_2 = k_3 = \frac{100 \ lbf}{ 12 \sqrt{3}}$

So, the forces are:

$\vec{F}_{cable_1} = k_1 (-4,0,4\sqrt{3})$

$\vec{F}_{cable_1} = \frac{100 \ lbf}{ 12 \sqrt{3}} (-4,0,4\sqrt{3})$

$\vec{F}_{cable_1} = (-\frac{100 \ lbf}{ 3 \sqrt{3}},0,\frac{100 \ lbf}{3})$

$\vec{F}_{cable_1} = (-19.245 \ lbf ,0, 33.333 \ lbf)$

$\vec{F}_{cable_2} = k_2 (2,2\sqrt{2},4\sqrt{3})$

$\vec{F}_{cable_2} = \frac{100 \ lbf}{ 12 \sqrt{3}} (2,2\sqrt{2},4\sqrt{3})$

$\vec{F}_{cable_2} = (9.622 \ lbf , 13.608 \ lbf ,33.333 \ lbf)$

$\vec{F}_{cable_3} = k_3 (2,-2\sqrt{2},4\sqrt{3})$

$\vec{F}_{cable_3} = \frac{100 \ lbf}{ 12 \sqrt{3}} (2,-2\sqrt{2},4\sqrt{3})$

$\vec{F}_{cable_3} = (9.622 \ lbf , -13.608 \ lbf ,33.333 \ lbf)$

5 0

4 years ago

During low-intensity activity, your body obtains most of its energy from

Gemiola [76]

Carbohydrates, in cellular respiration.

3 0

3 years ago

Panel A shows a ball shortly after being thrown upward. Panel B shows the same ball in an instant on its way down. Suppose air r

Anna11 [10]

Answer:

ur mom

Explanation:

6 0

3 years ago

A bicyclist travels at the speed of 25 kilometers per hour for 5 hours. How far does the bicyclist go?

mixas84 [53]

Answer:

125 kilometers

Explanation:

Speed= 25km/h

Time = 5 h

Distance= Speed x Time

= 25 x 5

= 125 km

6 0

3 years ago

Read 2 more answers