Find the value of a single resistor which is the combined equivalent of all resistors in the figure.

A gas cloud surrounds a dying star against a dark background. The star heats the gases in the cloud. What type of spectrum would

8090 [49]

There are several different types of spectrums that you could expect to find from
the gas cloud, but the best option from the list would be "<span>high-frequency spectrum".</span>

3 0

3 years ago

What is the mass of a car that has a kinetic energy if 4,320,000 J moving at 23 m/s?

Alekssandra [29.7K]

Answer:

kinetic energy=1/2mv^2.

which is 4320000=1/2×m×23^2.

which is 4320000=1/2×m×529.

4320000=264.5m.

m=4320000/264.5.

m=16332.70~16333g

4 0

3 years ago

A catapult launches a test rocket vertically upward from a well, giving the rocket an initial speed of 80.6 m/s at ground level.

kow [346]

Before the engines fail, the rocket's altitude at time <em>t</em> is given by

$y_1(t)=\left(80.6\dfrac{\rm m}{\rm s}\right)t+\dfrac12\left(3.90\dfrac{\rm m}{\mathrm s^2}\right)t^2$

and its velocity is

$v_1(t)=80.6\dfrac{\rm m}{\rm s}+\left(3.90\dfrac{\rm m}{\mathrm s^2}\right)t$

The rocket then reaches an altitude of 1150 m at time <em>t</em> such that

$1150\,\mathrm m=\left(80.6\dfrac{\rm m}{\rm s}\right)t+\dfrac12\left(3.90\dfrac{\rm m}{\mathrm s^2}\right)t^2$

Solve for <em>t</em> to find this time to be

$t=11.2\,\mathrm s$

At this time, the rocket attains a velocity of

$v_1(11.2\,\mathrm s)=124\dfrac{\rm m}{\rm s}$

When it's in freefall, the rocket's altitude is given by

$y_2(t)=1150\,\mathrm m+\left(124\dfrac{\rm m}{\rm s}\right)t-\dfrac g2t^2$

where $g=9.80\frac{\rm m}{\mathrm s^2}$ is the acceleration due to gravity, and its velocity is

$v_2(t)=124\dfrac{\rm m}{\rm s}-gt$

(a) After the first 11.2 s of flight, the rocket is in the air for as long as it takes for $y_2(t)$ to reach 0:

$1150\,\mathrm m+\left(124\dfrac{\rm m}{\rm s}\right)t-\dfrac g2t^2=0\implies t=32.6\,\mathrm s$

So the rocket is in motion for a total of 11.2 s + 32.6 s = 43.4 s.

(b) Recall that

${v_f}^2-{v_i}^2=2a\Delta y$

where $v_f$ and $v_i$ denote final and initial velocities, respecitively, $a$ denotes acceleration, and $\Delta y$ the difference in altitudes over some time interval. At its maximum height, the rocket has zero velocity. After the engines fail, the rocket will keep moving upward for a little while before it starts to fall to the ground, which means $y_2$ will contain the information we need to find the maximum height.

$-\left(124\dfrac{\rm m}{\rm s}\right)^2=-2g(y_{\rm max}-1150\,\mathrm m)$

Solve for $y_{\rm max}$ and we find that the rocket reaches a maximum altitude of about 1930 m.

(c) In part (a), we found the time it takes for the rocket to hit the ground (relative to $y_2(t)$ ) to be about 32.6 s. Plug this into $v_2(t)$ to find the velocity before it crashes:

$v_2(32.6\,\mathrm s)=-196\frac{\rm m}{\rm s}$

That is, the rocket has a velocity of 196 m/s in the downward direction as it hits the ground.

3 0

3 years ago

Choose the three statements that are true about valence electrons.

Varvara68 [4.7K]

We have that valence electrons poses the three characteristics stated, as

Group 14 (carbon group) are identified by 4 valence electrons.

Valence electrons of atoms are used to form bonds.

Group 14 (carbon group) are identified by 4 valence electrons.

Option A,B,C

<h3>Properties of Valence electrons</h3>

All elements in the same group or family have the same number of valence electrons: Yes, this is true as Group 14 (carbon group) are identified by 4 valence electrons.

Valence electrons are the only subatomic particles involved in forming bonds: Yes, Valence electrons of atoms are used to form bonds.

Carbon has 4 valence electrons because it is found in group 14:

True, Group 14 (carbon group) are identified by 4 valence electrons.

For more information on atoms visit

brainly.com/question/13981855

6 0

2 years ago

What is one benefit of lifelong physical activity?

kvasek [131]

The answer would be C

5 0

3 years ago