<h3>
Answer:</h3>
539.56 Joules
<h3>
Explanation:</h3>
- Efficiency of a machine is the ratio of work output to work input expressed as a percentage.
- Efficiency = (work output/work input) × 100%
- Efficiency of a machine is not 100% because so energy is lost due to friction of the moving parts and also as heat.
In this case;
Efficiency = 94%
Work input = 574 Joules
Therefore, Assuming work output is x
94% = (x/574 J) × 100%
0.94 = (x/574 J)
<h3>x = 539.56 J</h3>
Thus, you get work of 539.56 J from the machine
v = speed of the source of sound or the train towards the listener or switchman = 40 m/s
V = actual speed of sound = 340 m/s
f = actual frequency of sound as emitted from source or the train = 1000 Hz
f' = frequency as observed by the listener or by switchman = ?
Using Doppler's law , frequency observed by a listener from a source moving towards it is given as
f' = V f /(V - v)
inserting the values
f' = 340 x 1000 /(340 - 40)
f' = 340 x 1000/300
a) Cumulus is 100% the correct answer
