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3 years ago

Plants need to....................synthesize

Physics

1 answer:

koban [17]3 years ago

5 0

Answer:

nitrogen

Explanation:

because I also had this in exam and I was correct

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A screen door spring is stretched

bija089 [108]

Answer:

216.39 N/m

Explanation:

F = 64.7 N

x = 0.299 m

Plug those values into Hooke's Law:

F = kx

64.7 N = k(0.299 m)

---> k = 216.39 N/m

8 0

3 years ago

Jacki evaluated the expression below. 2 cubed (3 minus 1) + 4 (8 minus 12) = 2 cubed (2) + 4 (4) = 8 (2) + 16 = 16 + 16 = 32. Wh

Naddika [18.5K]

Answer:

Her error was that she did not subtract 12 from 8 correctly

Explanation:

Jackie did 8-12 instead of 12-8

8 0

3 years ago

Describe an experiment to show that air support burning

noname [10]

Take a small burning candle. ... After few minutes the candle is extinguished. As the supply of air is stopped due to glass jar the burning of candle is also stopped. This experiment proves that air supports burning.

3 0

3 years ago

Derive the velocity of an electron in a hydrogen atom using Bohr's model. The electron has a mass of m, charge of (-e) and an or

Ahat [919]

Answer:

$v=\frac{Ze^2}{2 \epsilon_0\times n\times h}$

$v=\frac {2.185\times 10^6}{n}\ m/s$

Explanation:

According to Bohr's Theory,

The force of attraction acting between the electron and the nucleus is equal to the centrifugal force acting on the electron.

Thus,

$\frac{Ze^2}{4\pi \epsilon_0 r^2}=m_e\frac{v^2}{r}$ ......1

Where, Z is the atomic number or the number of protons

r is the atomic radius

v is the velocity of the electron

$m_e$ is the mass of the electron

Also,

Accoriding to Bohr, the angular momentum is quantized. He states that the angular momemtum is equal to the integral multiple of $\frac {h}{2\times \pi}$ .

$m_e vr=n\times \frac {h}{2\times \pi}$ ....2

solving r from equation 2, we get that:

$r=n\times \frac {h}{2\times \pi\times m_e v}$

Putting in 1 , we get that:

$v=\frac{Ze^2}{2 \epsilon_0\times n\times h}$

Applying values for hydrogen atom,

Z = 1

Mass of the electron ( $m_e$ ) is 9.1093×10⁻³¹ kg

Charge of electron (e) is 1.60217662 × 10⁻¹⁹ C

$\epsilon_0$ = 8.854×10⁻¹² C² N⁻¹ m⁻²

h is Plank's constant having value = 6.626×10⁻³⁴ m² kg / s

We get that:

$v=\frac {2.185\times 10^6}{n}\ m/s$

4 0

4 years ago

A certain satellite has a kinetic energy of 7.5 billion joules at perigee (closest to Earth) and 6.5 billion joules at apogee (f

Elena L [17]

Answer:

Work Done by the earth's gravitational force on the satellite as it travels from apogee to perigee is

W = F*D*Cos90° = 0

Explanation:

Although there is a change in the kinetic energy of the satellite at the apogee and perigee, the work done by the earth's gravitational force on the satellite is Zero.

W = F.D, F is the gravitational force, D is the displacement. Both F and D are vectors and perpendicular to each other. That is, the angle between F and D is 90°.

8 0

3 years ago