Answer:
61578948 m/s
Explanation:
λ
 = λ
 
687 = 570 
 = 61578948 m/s
So Slick Willy was travelling at a speed of 61578948 m/s to observe this.
 
        
                    
             
        
        
        
Answer:
   h = v₀² / 2g
,      h = k/4g     x²
Explanation:
In this exercise we can use the law of conservation of energy at two points, the lowest, before the shot and the highest point that the mouse reaches
Starting point. Lower compressed spring
               Em₀ = K = ½ m v²
Final point. Highest on the path
              
 = U = mg h
              
As or no friction the energy is conserved  
               Em₀ =  Em_{f}
               ½ m v₀²² = m g h
              h = v₀² / 2g
We can also use as initial energy the energy stored in the spring that will later be transferred to the mouse
                   ½ k x² = 2 g h
                   h = k/4g     x²
 
        
                    
             
        
        
        
Answer:
Explanation:
Moment of inertia of larger disk   I₁ = 1/2 MR²
Moment of inertia of smaller  disk   I₂ = 1/2 m r ²
Initial angular velocity
We shall apply law of conservation of angular momentum . 
initial total momentum = final angular momentum
I₁ X ωi  = ( I₁ + I₂ )ωf
1/2 MR² x ωi = 1/2 ( m r² + MR² ) ωf
ωf =  ωi   / ( 1 + m r²/MR² ) 
 
        
             
        
        
        
Answer:
The speed of the light signal as viewed from the observer is c.
Explanation:
Recall the basic postulate of the theory of relativity that the speed of light is the same in ALL inertial frames. Based on this, the speed of light is independent of the motion of the observer. 
 
        
             
        
        
        
Answer:
the required mass flow rate is 49484.37 kg/s
 
Explanation:
Given the data in the question;
we first determine the relation for mass flow rate of water that passes through the turbine;
so the relation for net work on the turbine due to the change in potential energy considering 100% efficiency is;
 = m ( Δ P.E )
so we substitute (gh) for ( Δ P.E );
 = m (gh)
m = 
 / gh
so we substitute our given values into the equation 
m = 100 MW / ( 9.81 m/s²) × 206 m 
m = ( 100 MW × 10⁶W/MW) / ( 9.81 m/s²) × 206 m 
m = 10 × 10⁷ / 2020.86
m = 49484.37 kg/s
Therefore, the required mass flow rate is 49484.37 kg/s