Potential energy= mass x gravitational field x height
        
             
        
        
        
Answer:
Because of the presence of air resistance
Explanation:
When an object is in free fall, ideally there is only one force acting on it:
- The force of gravity, W = mg, that pushes the object downward (m= mass of the object, g = acceleration of gravity)
However, this is true only in absence of air (so, in a vacuum). When air is present, it exerts a frictional force on the object (called air resistance) with upward direction (opposite to the motion of free fall) and whose magnitude is proportional to the speed of the object.
Therefore, it turns out that as the object falls, its speed increases, and therefore the air resistance acting against it increases too; as a result, the at some point the air resistance becomes equal (in magnitude) to the force of gravity: when this happens, the net acceleration of the object becomes zero, and so the speed of the object does not increase anymore. This speed reached by the object is called terminal velocity.
 
        
             
        
        
        
The frequency of note C3 is 131 
.
<u>Explanation:</u>
Frequency is the measure of repetition of same thing a certain number of times. So frequency is inversely proportional to the wavelength. As wavelength is distance between two successive crests or troughs in a sound wave.
And frequency is the completion of number of cycles in a given time in sound waves. The frequency and wavelength are inversely proportional to each other with velocity of sound being the proportionality constant.
 Thus, here the speed of sound is given as 343 m/s, the wavelength of the note is also given as 2.62 m, then frequency will be as follows:

Thus,

So the frequency of note C3 is 131 
.
 
        
             
        
        
        
The net force on the student is A) -294 N
Explanation:
Neglecting air resistance, there is only one force acting on the student: the force of gravity, which is given by

where
m is the mass of the student
g is the acceleration of gravity
In this problem, we have:
m = 30 kg is the mass of the student
 is the acceleration of gravity, where the negative sign means the direction is downward
Substituting, we find the force of gravity on the student:

And since this is the only force acting on the student, it is also the net force on him.
Learn more about gravitational force:
brainly.com/question/1724648
brainly.com/question/12785992
#LearnwithBrainly
 
        
             
        
        
        
Answer:
frequency or wavelength
Explanation:
this is why the electromagnetic spectrum has a decreasing wavelength and increasing frequency