Answer:
The answer is not B or D because they need light co2 and water to make their food so B and D are out. and unless someone is walking during winter to feed it. It will not be A so the answer is C.
Explanation:
Answer:
a) m = 69.0 kg
b) release some gas in the opposite direction to the astronaut's movement
Explanation:
a) Let's use Newton's second law
F = m a
m = F / a
m = 60.0 / 0.870
m = 69.0 kg
b) when we exert a force on the astronaut it acquires a momentum po, as the astronaut system plus spacecraft is isolated, the momentum is conserved
p₀ = p_f
m v = M v '
v ’= 
so we see that the ship is moving backwards, but since the mass of the ship is much greater than the mass of the astronaut, the speed of the ship is very small.
One method to avoid this effect is to release some gas in the opposite direction to the astronaut's movement so that the initial momentum of the astronaut plus the gas is zero and therefore no movement is created in the spacecraft.
We need to charge a metal sphere positively without touching it. This can be achieved using electrostatic induction.
At critical temperature, the resistivity of the superconductor
B. It suddenly drops to zero
Explanation:
Materials can be classified into three different types depending on their resistance:
- Conductors: these materials have generally low resistance and allow electricity to pass through easily. The resistance of a conductor increases linearly with the temperature
- Insulators: these materials do not allow electricity to pass through - so they have very high resistance
- Semi-conductors: these are materials that are insulators are room temperature, however they becomes conductors when heated. Therefore, the resistance of a semiconductor decreases when the temperature increases
- Superconductors: these are special materials that are normally conductors; however, at very low temperatures (we are talking about temperature very near to 0 K), their resistance becomes suddenly zero.
Therefore, the correct answer is:
B. It suddenly drops to zero
Learn more about current and resistance:
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