Missing question: "how much work is done by the teacher?" (found on internet)
Solution:
The work done to move the desk across the floor is equal to
where F is the horizontal force applied to move the desk, and d is the distance covered by the desk. If we use F=20 N and d=5 m, we find the work done:
Infra sounds are sounds with frequencies below 20 Hz.The popular concept that infra sounds are in audible holds false
Explanation:
- Some example of Infrasounds are- some animals such as whales, elephants and giraffes which communicate with each other using infrasound over long distances.
- Various natural phenomenon such as Avalanches, volcanoes, earthquakes, ocean waves, water falls and meteors also generate infrasonic waves
- Infrasound, is sound that is lower in frequency than 20 Hz or cycles per second.
- Even the human body can generate mechanical vibrations at very low frequencies, which are known as the infrasonic waves. Such low-frequency vibrations/infrasonic waves are produced by physiological processes—such as heartbeats, respiratory movements, blood flow in vessels, and other processes.
The work and energy theorem allows finding the result for where the kinetic energy of the car is before stopping is:
The energy becomes:
- An important part in work on discs.
- A part in non-conservative work due to friction.
Work is defined by the scalar product of force and displacement.
W = F . d
Where the bold indicate vectors, W is work, F is force and d is displacement.
The work energy theorem relates work and kinetic energy.
W = ΔK = 
In this case the vehicle stops therefore its final kinetic energy is zero, consequently the work is:
W = - K₀
Therefore, the initial kinetic energy that the car has is converted into work in its brakes. In reality, if assuming that there is friction, an important part is transformed into non-conservative work of the friction force, this work can be seen in a significant increase in the temperature of the discs on which the work is carried out.
In conclusion, using the work-energy theorem we can find the result for where the kinetic energy of the car is before stopping is:
The energy becomes:
- An important part in work on the discs.
- A part in non-conservative work due to friction.
Learn more here: brainly.com/question/17056946
Answer:
Wavelength, 
Frequency, 
Explanation:
We need to find the intensity of the radiation is a maximum for a black body at 298 K. It can be calculated using Wein's displacement law. It is given by :
Here, T = 298 K
If f is the frequency of black body radiation. It is given by :
Hence, this is the required solution.
