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ohaa [14]
3 years ago
9

Why is sun called a source of light??​

Physics
1 answer:
mote1985 [20]3 years ago
3 0

Answer:

because he give heat and energy

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O ln a hydraulic press , a force Of 400 N is exerted on
egoroff_w [7]

Explanation:

Pressure = force / area

P = 400 N / 0.001 m²

P = 400,000 Pa

7 0
3 years ago
Definition These are the components of the reservoirs of oxygen that are exchanged in our environment.
andrew11 [14]

Answer:

Oxygen cycle

Explanation:

The components of the reservoirs of oxygen that are exchange in our environment is the oxygen cycle

It suggests the movement of oxygen between the living and non-living parts.

  • The cycle does not account for oxygen that is trapped and cannot be exchanged in nature.
  • Oxygen is important component of the atmosphere.
  • Gaseous exchange between living organisms and atmosphere involves oxygen to a very large extent.
4 0
3 years ago
A 525 kg satellite is in a circular orbit at an altitude of 575 km above the Earth's surface. Because of air friction, the satel
Dafna1 [17]

Answer:

1.69\cdot 10^{10}J

Explanation:

The total energy of the satellite when it is still in orbit is given by the formula

E=-G\frac{mM}{2r}

where

G is the gravitational constant

m = 525 kg is the mass of the satellite

M=5.98\cdot 10^{24}kg is the Earth's mass

r is the distance of the satellite from the Earth's center, so it is the sum of the Earth's radius and the altitude of the satellite:

r=R+h=6370 km +575 km=6945 km=6.95\cdot 10^6 m

So the initial total energy is

E_i=-(6.67\cdot 10^{-11})\frac{(525 kg)(5.98\cdot 10^{24} kg)}{2(6.95\cdot 10^6 m)}=-1.51\cdot 10^{10}J

When the satellite hits the ground, it is now on Earth's surface, so

r=R=6370 km=6.37\cdot 10^6 m

so its gravitational potential energy is

U = -G\frac{mM}{r}=-(6.67\cdot 10^{-11})\frac{(525 kg)(5.98\cdot 10^{24}kg)}{6.37\cdot 10^6 m}=-3.29\cdot 10^{10} J

And since it hits the ground with speed

v=1.90 km/s = 1900 m/s

it also has kinetic energy:

K=\frac{1}{2}mv^2=\frac{1}{2}(525 kg)(1900 m/s)^2=9.48\cdot 10^8 J

So the total energy when the satellite hits the ground is

E_f = U+K=-3.29\cdot 10^{10}J+9.48\cdot 10^8 J=-3.20\cdot 10^{10} J

So the energy transformed into internal energy due to air friction is the difference between the total initial energy and the total final energy of the satellite:

\Delta E=E_i-E_f=-1.51\cdot 10^{10} J-(-3.20\cdot 10^{10} J)=1.69\cdot 10^{10}J

8 0
3 years ago
Quick! how did Daniel hale Williams contribute to science?
My name is Ann [436]
He preformed the first ever successful open heart surgery
3 0
3 years ago
A shopping cart rolls from x=19.9m to x=5.40m with an average velocity of -0.418m/s. How much time did it take? (unit=s)
andrew11 [14]

Given

initial position = Xi= 19.9m

Final position Xf = 5.4m

Average velocity= Va = -0.418m/s

it shows displacement is reverse.

To find  t=?

As   Va = (Xf- Xi) / t

t = (Xf-Xi) / ( Va)

t = ( 5.4-19.9) / (-0.418)

t = (-14.5 ) / (-0.418)   (-ve sign cancel out at numerator and denominator)

t =34.69 s

8 0
3 years ago
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