Well, we know that the total energy in a closed system remains constant.
The problem with the story of Eva is that she is not in a closed system.
If the dark room were really a closed system, then she could press the
button or turn the switch all day, and the lamp could not light. It needs
electrical energy coming in from somewhere in order to turn on.
Let's say that Eva used her arm muscles to strike a match and light the
candle on the table. Then we would have have food energy, muscle
energy, chemical energy in the match, chemical energy in the candle,
heat and light energy coming out of the candle, heat energy soaking into
her hand, light energy bouncing off of the book and into her eyes ... all
going on during the story, and the sum total of all of them would remain
constant.
Answer: B. I hope you get this right.
Answer:
1. Doppler Effect = The apparent change in frequency perceived when the source of sound is approaching or moving away from an observer
2. Beats = The vibration of an object at its natural frequency, caused by a force or wave of the same frequency
3. Resonance = a series of alternating reinforcements and cancellations produced by the interference of waves
4. Shockwave = The cone-shaped wave made by a particle moving faster than the speed of a wave in that medium
Explanation:
I hope this helps. :)
The height of stairs a 60 kg student would have to run in order to burn off 1 Calorie of food energy will be 7.1 meters.
<h3>What is potential energy?</h3>
The potential energy is due to the virtue of the position and the height. The unit for the potential energy is the joule.
Given data;
Mass of student,m = 60 kg
Energy,E = 4190 J
Height of stairs,h=?
The potential energy is mainly dependent upon the height of the object. The potential energy is found as;
Potential energy = mgh
E=mgh
h=E/mg
h= 4190 J / (60 kg× 9.81 m/s²)
h = 7.1 metre
Hence the height of the stairs will be 7.1 meters.
To learn more about the potential energy, refer to the link;
brainly.com/question/24284560
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