100kg x bicycle speed = 1400 X 2
bicycle speed = 2800/ 100
bicycle speed = 28 m/s
        
             
        
        
        
D. 
The reading between 7N and 8N would have to be 7.5N. Answers A and B are much to small and answer C is way to big.
        
                    
             
        
        
        
The energy of moving electrical charges is Electrical energy
Hope its the answer you are finding and hope it helps....
        
             
        
        
        
I already answered this quesiton. The fact is that there are only two kind of poles and since the two taped poles of the magnets labeled A and B attracts one to each other, we know that the two taped poles of the first two magnets are oppsosite.
Then, the taped pole of the third magnet has to be equal to one of the first two taped poles and opposite to the other of the first two taped poles.
That drives you to conclude (predict)  that when she brings the taped end of the third magnet (magnet C) near each of the first two magntes, in one case they will attract each other and in the other case they will repele mutually.
        
             
        
        
        
We can calculate the acceleration of Cole due to friction using Newton's second law of motion:

where 

 is the frictional force (with a negative sign, since the force acts against the direction of motion) and m=100 kg is the mass of Cole and the sled. By rearranging the equation, we find

Now we can use the following formula to calculate the distance covered by Cole and the sled before stopping:

where

 is the final speed of the sled

 is the initial speed

 is the distance covered
By rearranging the equation, we find d:
