<h3><u>Answer;</u></h3>
= 75 %
<h3><u>Explanation</u>;</h3>
To measure efficiency of a machine, compare the work output to work input.
Efficiency = Work output/ work output × 100 %
= 300/400 × 100
= 75 %
Answer:
331.28 K
Explanation:
To solve this problem, you need to know that the heat that the water at 373 K is equal to the heat that the water at 285 K gains.
First, we will asume that at the end of this process there won't be any water left in gaseous state.
The heat that the steam (H20(g)) loses is equal to the heat lost because the change of phase plus the heat lost because of the decrease in temperature:

The specific Heat c of water at 298K is 4.18 kJ/K*kg.
The latent heat cl of water is equal to 2257 kJ/kg.
The heat that the cold water gains is equal to heat necessary to increase its temperature to its final value:

Remember that in equilibrium, the final temperature of both bodies of water will be equal.
Then:

Correct answer choice is:
D. A frequency higher than the original frequency.
Explanation:
This is a true case of Doppler's effect. The Doppler effect can be defined as the effect originated by a traveling source of waves in which there is a visible higher variation in pulse for observers towards what the source is progressing and a visible descending shift in rate for observers from what the source is dropping.
Answer:
its good no need to change anything :))
Work= Force x Distance
Answer: 7500 Joules