The law of conservation of energy states that energy is not created nor destroyed, rather it is only transferred or transmitted from one form to another. Now, the work exerted which is the input is only transformed to move the object which is now becomes the output work. Some are used to move the object, some are converted to other forms. That is why it is never greater than the input energy. Thank you for your question. Please don't hesitate to ask in Brainly your queries. 
        
                    
             
        
        
        
Forget about the car's speed.  You don't need it.
The tires spin 840 rpm.  That's 840 <em>Revolutions per Minute</em> . 
There are 60 seconds in 1 minute.  So something that happens 840 times in 1 minute happens (840 / 60) times every second.
(840 rev per minute) / (60)  =  <em>14 revs per second</em> .
 
        
             
        
        
        
Answer:
Explanation:
Our lunar companion rotates while it orbits Earth. It's just that the amount of time it takes the moon to complete a revolution on its axis is the same it takes to circle our planet — about 27 days. As a result, the same lunar hemisphere always faces Earth.
 
        
                    
             
        
        
        
Quantity of Charge , Q = ne
Where n = number of electrons
             e = charge on one electron = -1.6 * 10 ^-19  C.
             n = 50 * 10^31  electrons
Q =    (50 * 10^31)*( -1.6 * 10 ^-19 ) =  -8 * 10^13 C.
Note that the minus sign indicates that the charge is a negative charge.