Answer: 
Democritus had no scientific instruments to extend the reach of his senses, so all of his experiments were just 'mind experiments', but because Democritus was a philosopher, he thought more into depth about why we humans are alive which led to the atomic theory.
Explanation:
 
        
             
        
        
        
Answer:
The beat frequency is 30 Hz
Explanation:
Given;
velocity of the two sound waves, v = 343 m/s
wavelength of the first wave, λ₁ = 5.72 m
wavelength of the second wave, λ₂ = 11.44 m
The frequency of the first wave is calculated as follows;
F₁ = v/λ₁
F₁ = 343 / 5.72 
F₁ = 59.97 HZ
The frequency of the second wave is calculated as follows;
F₂ = v/λ₂
F₂ = 343 / 11.44
F₂ = 29.98 Hz
The beat frequency is calculated as;
Fb = F₁ - F₂
Fb =  59.97 HZ - 29.98 Hz
Fb = 30 Hz
 
        
             
        
        
        
Set up a proportion
1 mile/1.6 km = 20,000miles/x
Cross Multiply
x = (20,000) * (1.6)
x = 32,000 kilometers
        
                    
             
        
        
        
Answer:
1050 kg
Explanation:
The formula for kinetic energy is:
KE (kinetic energy) = 1/2 × m × v² where <em>m</em> is the <em>mass in kg </em>and <em>v</em> is the velocity or <em>speed</em> of the object <em>in m/s</em>.
We can now substitute the values we know into this equation.
KE = 472 500 J and v = 30 m/s:
472 500 = 1/2 × m × 30²
Next, we can rearrange the equation to make m the subject and solve for m:
m = 472 500 ÷ (1/2 × 30²)
m = 472 500 ÷ 450
m = 1050 kg
Hope this helps!
 
        
                    
             
        
        
        
Part A:
For this part we’re assuming all the kinetic energy of the moving bumper car is converted into elastic potential energy in the spring since the car is brought to rest. Therefore you can find the total kinetic energy to get your answer:
KE = ½ mv^2
KE = ½ (200)(8)^2
KE = 6400 J
Part B:
Now you can use Hooke’s law to find the force:
F = kx
F = (5000)(0.2)
F = 1000 N