Hello, 
To solve we need to know the formula for speed
The formula is D/T=S     (Distance of time=speed)
Now all we have to do is plug in the numbers. 
20/40= 1/2 or 0.5
SO the speed is 0.5 m/s
Have a great day!
 
        
             
        
        
        
Answer:
a = 3.61[m/s^2]
Explanation:
To find this acceleration we must remember newton's second law which tells us that the total sum of forces is equal to the product of mass by acceleration.
In this case we have:
![F = m*a\\\\m=mass = 3.6[kg]\\F = force = 13[N]\\13 = 3.6*a\\a = 3.61[m/s^2]](https://tex.z-dn.net/?f=F%20%3D%20m%2Aa%5C%5C%5C%5Cm%3Dmass%20%3D%203.6%5Bkg%5D%5C%5CF%20%3D%20force%20%3D%2013%5BN%5D%5C%5C13%20%3D%203.6%2Aa%5C%5Ca%20%3D%203.61%5Bm%2Fs%5E2%5D)
 
        
             
        
        
        
Answer:
 m₁ / m₂ = 1.3
Explanation:
We can work this problem with the moment, the system is formed by the two particles
The moment is conserved, to simulate the system the particles initially move with a moment and suppose a shock where the particular that, without speed, this determines that if you center, you should be stationary, which creates a moment equal to zero
     p₀o = m₁ v₁ + m₂ v₂
     pf = 0
     m₁ v₁ + m₂ v₂ = 0
     m₁ / m₂ = -v₂ / v₁
     m₁ / m₂=  - (-6.2) / 4.7
      m₁ / m₂ = 1.3
Another way to solve this exercise is to use the mass center relationship
     Xcm = 1/M    (m₁ x₁ + m₂ x₂)
We derive from time
    Vcm = 1/M   (m₁ v₁ + m₂v₂)
As they say the velocity of the center of zero masses
     0 = 1/M   (m₁ v₁ + m₂v₂)
    m₁ v₁ + m₂v₂ = 0
     m₁ / m₂ = -v₂ / v₁
    m₁ / m₂ = 1.3
 
        
             
        
        
        
Answer:
The only difference between radio waves, visible light and gamma rays is the energy of the photons.'
Bothrays have photons, but in radio waves they are weaker.