Answer:
so initial speed of the rock is 30.32 m/s
correct answer is b. 30.3 m/s
Explanation:
given data 
h = 15.0m 
v = 25m/s 
weight of the rock m = 3.00N  
solution
we use here work-energy theorem that is express as here 
work = change in the kinetic energy    ..............................1
so it can be written as 
work = force × distance     ...................2
and 
KE is express as 
K.E = 0.5 × m × v²  
and it can be written as 
F × d = 0.5 × m × (vf)² - (vi)²      ......................3 
here 
m is mass and vi and vf is initial and final velocity 
F = mg = m  (-9.8)  , d = 15 m and v{f} = 25 m/s
so put value in equation 3 we get 
m  (-9.8) × 15 = 0.5 × m × (25)² - (vi)² 
solve it we get 
(vi)² =  919 
vi = 30.32 m/s
so initial speed of the rock is 30.32 m/s
 
        
             
        
        
        
D=m÷v
so density would be 57.9 ÷ 3 = 19.3 g/cm³
        
                    
             
        
        
        
Answer:
Check the correctness of the relation c=1 √μ0∈0 where the symbols have their usual meaning. check-circle.
 
        
             
        
        
        
Answer:
Physical education provides cognitive content and instruction designed to develop motor skills, knowledge, and behaviors for physical activity and physical fitness. Supporting schools to establish physical education daily can provide students with the ability and confidence to be physically active for a lifetime.
 
        
                    
             
        
        
        
Answer:
I think it would be GFI outlet 
Explanation:
 Ground Fault Circuit Interrupter (GFI) device protects us from receiving electric shocks from faults in the electrical devices we use in our home. (resource Google)