A non reactive metal can be identified from other metals because it's surface is?

Leta Stetter Hollingworth conducted pioneering work on __________. A. identity development in ethnic minorities B. cognitive pro

rusak2 [61]

I believe the correct answer from the choices listed above is option D. Leta Stetter Hollingworth conducted pioneering work on adolescent development and gifted children. She <span>was an American psychologist who conducted pioneering work in the early 20th century. </span>

5 0

3 years ago

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Why are different constellations<br> of stars seen during different<br> seasons?

slamgirl [31]

Actually, they're not. There's a group of stars and constellations arranged
around the pole of the sky that's visible at any time of any dark, clear night,
all year around. And any star or constellation in the rest of the sky is visible
for roughly 11 out of every 12 months ... at SOME time of the night.

Constellations appear to change drastically from one season to the next,
and even from one month to the next, only if you do your stargazing around
the same time every night.

Why does the night sky change at various times of the year ? Here's how to
think about it:

The Earth spins once a day. You spin along with the Earth, and your clock is
built to follow the sun . "Noon" is the time when the sun is directly over your
head, and "Midnight" is the time when the sun is directly beneath your feet.

Let's say that you go out and look at the stars tonight at midnight, when you're
facing directly away from the sun.

In 6 months from now, when you and the Earth are halfway around on the other
side of the sun, where are those same stars ? Now they're straight in the
direction of the sun. So they're directly overhead at Noon, not at Midnight.

THAT's why stars and constellations appear to be in a different part of the sky,
at the same time of night on different dates.

5 0

4 years ago

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A person pulls a bucket of water up from a well with a rope. Assume the initial and final speeds of the bucket are zero (Vi-Vf-0

n200080 [17]

Answer:

a

This a closed system because the mass of the system is conserved

The energy system that undergoes change is the Potential energy system

The energy system diagram is shown on the first uploaded image

b

Work done = Change in gravitational potential energy

So solving algebraically for work done would be

Work done = $m*g*h$

where m is mass

g is acceleration due to gravity

and h is the height

c

Work done in terms of force and distance is = mg

where m is mass of bucket and

g is acceleration due to gravity

Explanation:

a) At the start, potential and kinetic energy were zero. so, energy is zero.

As the person pulls the bucket up, the potential energy becomes mgh.

so,final energy will be consisting of only potential energy.

B) Here work done is equal to change in gravitational potential energy.

W = $\Delta P.E$

W = m*g*h

where g = 9.9 m/ $s^2$

C) Work = force * distance

mgh = force * h

force = mg

force = weight of bucket

6 0

3 years ago

Water has a specific heat capacity nearly nine times that of iron. Suppose a 50-g pellet of iron at a temperature of 200∘C is dr

miv72 [106K]

Answer:

a. closer to 20∘C

Explanation:

$m_{p}$ = mass of pallet = 50 g = 0.050 kg

$c_{p}$ = specific heat of pallet = specific heat of iron

$T_{pi}$ = Initial temperature of pellet = 200 C

$m_{w}$ = mass of water = 50 g = 0.050 kg

$c_{w}$ = specific heat of water

$T_{wi}$ = Initial temperature of water = 20 C

$T_{e}$ = Final equilibrium temperature

Also given that

$c_{w} = 9 c_{p}$

Using conservation of energy

Energy gained by water = Energy lost by pellet

$m_{w} c_{w} (T_{e} - T_{wi}) = m_{p} c_{p} (T_{pi} - T_{e})\\(0.050) (9) c_{p} (T_{e} - 20) = (0.050) c_{p} (200 - T_{e})\\ (9) (T_{e} - 20) = (200 - T_{e})\\T_{e} = 38 C$

hence the correct choice is

a. closer to 20∘C

4 0

4 years ago

When Earth and the Moon are separated by a

Wewaii [24]

Using the Universal Gratitation Law, we have:

$F= \frac{MmG}{d^2} \\ MmG=2*10^{20}*(3.84*10^8)^2 \\ MmG=29.4912*10^36$

Again applying the formula in the new situation, comes:

$F= \frac{MmG}{d^2} \\ F= \frac{29.4912*10^36}{(1.92*10^8)^2} \\ \boxed {F=8*10^{20}}$

Number 4

If you notice any mistake in my english, please let me know, because i am not native.

6 0

4 years ago

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