<span>No machine can operate at 100 percent efficiency because some of the energy input will always be used to overcome the force of gravity and the effects of friction and air resistance.</span>
        
                    
             
        
        
        
Answer:
This is a paradox — an inconsistency that often leads people to think that time travel cannot occur in our universe." A variation is known as the "grandfather paradox" — in which a time traveler kills their own grandfather, in the process preventing the time traveler's birth
Explanation:
hope this Wil help ....
 
        
             
        
        
        
Answer:
Force: Strength or energy as an attribute of physical action or movement.
 
        
                    
             
        
        
        
Gravitational acceleration is approx 9.8 m/s
Time is 7s
a=9.8 m/s
t=7s
a = d/t^2
therefore:
d = a * t^2
d = 9.8 * 7^2
d = 9.8 * 49
d = 480.2 [m]
 
        
             
        
        
        
In a parallel connection, the equivalent resistance is the summation of the inverse of each individual resistances. It is mathematically expressed as 1/ Req = 1/10 +1/20 + 1/25 = 5.263 ohms. Also, the voltage across each resistor is equal to the input voltage, therefore I = 100 / 10 = 10 Amps. I hope this helped you.