Answer:
A) some of the rocks energy is transformed to thermal energy 
Explanation:
If we neglect air resistance during the fall of the rock, than the mechanical energy of the rock (which is sum of its potential energy and its kinetic energy) would be constant during the entire motion, so the total energy of the rock at the top would be the same as the sum of its potential energy and kinetic energy at the bottom.
However, this not occurs, due to the presence of air resistance. In fact, air resistance acts against the fall of the rock, and because of the friction between the molecules of air and the surface of the rock, the rock loses part of its energy. This energy is converted into thermal energy of the molecules of the air.
 
        
             
        
        
        
Liquid and solid water were not in the giant gas cloudr
        
                    
             
        
        
        
Answer:
(a) Magnitude of Vector = 207.73 m
(b) Direction = 65.48° 
Explanation:
(a)
The formula to find out the magnitude of a resultant vector with the help of its x and y components is given as follows:

<u>Magnitude of Vector = 207.73 m</u>
(b)
For the direction of the vector we have the formula:

<u>Direction = 65.48°</u>
 
        
             
        
        
        
Answer:
a)   x = ⅔ d
, b) the charge must be negative, c) Q
Explanation:
a) In this exercise the force is electric between the charges, we are asked that the system of the three charges is in equilibrium, we use Newton's second law. Balance is on the third load that we are placing
          ∑ F = 0
         -F₁₂ + F₂₃ = 0
          F₁₂ = F₂₃
          
let's replace the values
         k Q Q / r₁₂² = k Q 4Q / r₂₃²
             Q² / r₁₂² = 4 Q² / r₂₃²
suppose charge 3 is placed at point x
         r₁₂ = x
         r₂₃ = d-x
              
we substitute
              1 / x² = 4 / (d-x) 2
              1 / x = 2 / (d-x)
              x = 2 (x-d)
              x = 2x -2d
             3x = 2d
               x = ⅔ d
b) The sign of the charge must be negative, to have an attractive charge on the two initial charges
c)  Q