As the temperature decreases, the rate of radiation goes down, but the radiation exists as long as the temperature is above the absolute zero, which is actually 0 Kelvin. 0 Kelvin equals -273°C or -460°F. All objects in the world radiate if above that temperature.
Answer:
4. All of the above I think, not to sure about 1. but the rest are right so im like 90.99999 percent sure good luck
Answer:
When it's closest to the sun.
Explanation:
The force of gravity acting on a planet is equal to its mass times its centripetal acceleration.
Fg = m v^2 / r
The force of gravity is defined by Newton's law of universal gravitation as:
Fg = mMG / r^2
Therefore:
mMG / r^2 = m v^2 / r
MG / r = v^2
v increases as r decreases. So the planet is moving fastest when it's closest to the sun, also known as the <em>perihelion</em>.
Answer:
A. -2.16 * 10^(-5) N
B. 9 * 10^(-7) N
Explanation:
Parameters given:
Distance between their centres, r = 0.3 m
Charge in first sphere, Q1 = 12 * 10^(-9) C
Charge in second sphere, Q2 = -18 * 10^(-9) C
A. Electrostatic force exerted on one sphere by the other is:
F = (k * Q1 * Q2) / r²
F = (9 * 10^9 * 12 * 10^(-9) * -18 * 10^(-9)) / 0.3²
F = -2.16 * 10^(-5) N
B. When they are brought in contact by a wire and are then in equilibrium, it means they have the same final charge. That means if we add the charges of both spheres and divided by two, we'll have the final charge of each sphere:
Q1 + Q2 = 12 * 10^(-9) + (-18 * 10^(-9))
= - 6 * 10^(-9) C
Dividing by two, we have that each sphere has a charge of -3 * 10^(-9) C
Hence the electrostatic force between them is:
F = [9 * 10^9 * (-3 * 10^(-9)) * (-3 * 10^(-9)] / 0.3²
F = 9 * 10^(-7) N
The amount of heat given by the water to the block of ice can be calculated by using
where
is the mass of the water
is the specific heat capacity of water
is the variation of temperature of the water.
Using these numbers, we find
This is the amount of heat released by the water, but this is exactly equal to the amount of heat absorbed by the ice, used to melt it into water according to the formula:
where
is the mass of the ice while
is the specific latent heat of fusion of the ice.
Re-arranging this formula and using the heat Q that we found previously, we can calculate the mass of the ice:
