Which of the following describes the efficiency of real machines?
2 answers:
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The amount of heat required is B) 150 J
Explanation:
The amount of heat energy required to increase the temperature of a substance is given by the equation:
where:
m is the mass of the substance
C is the specific heat capacity of the substance
is the change in temperature of the substance
For the sample of copper in this problem, we have:
m = 25 g (mass)
C = 0.39 J/gºC (specific heat capacity of copper)
(change in temperature)
Substituting, we find:
So, the closest answer is B) 150 J.
Learn more about specific heat capacity:
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Answer:
32 seconds
Explanation:
m1 = 80 kg
m2 = 10 kg
v2 = 5m/s
According to the property of conservation of momentum, assuming that both you and the bag are stationary before the safety rope comes lose:
Since the space station is 20 meters away, the time taken to reach it is given by:
It takes you 32 seconds to reach the station.