Answer:
V = V0 + a t
V = 75 - 9.8 * 3 = 45.6 m/s
 
        
             
        
        
        
Answer:-2.61 m/s
Explanation:
This problem can be solved by the Conservation of Momentum principle, which establishes that the initial momentum  must be equal to the final momentum
 must be equal to the final momentum  :
:
 (1)
 (1)
Where:
 (2)
 (2)
 (3)
 (3)
 is the mass of the first car
 is the mass of the first car
 is the velocity of the first car, to the North
 is the velocity of the first car, to the North
 is the mass of the second car
 is the mass of the second car
 is the mass of the second car, to the South
 is the mass of the second car, to the South
 is the final velocity of both cars after the collision
 is the final velocity of both cars after the collision
 (4)
 (4)
Isolating  :
:
 (5)
 (5)
 (6)
 (6)
Finally:
 (7) This is the resulting velocity of the wreckage, to the south
 (7) This is the resulting velocity of the wreckage, to the south
 
        
             
        
        
        
Hydrogen has one proton whereas helium has two protons in its nucleus.
<h3>How hydrogen and helium atoms different from one another?</h3>
Atoms of hydrogen have a single proton in their nucleus and a single electron in the lowest energy level while on the other hand, Helium atoms have two protons in the nucleus  and two electrons in the lowest energy level. In this way, we can say that the atomic number of hydrogen is 1 whereas the atomic number of helium is 2 because of the presence of two protons. Hydrogen atom has no neutron while on the other hand, the helium atom has one neutron in its nucleus.
So we can conclude that Hydrogen has one proton whereas helium has two protons in its nucleus.
Learn more about atom here: brainly.com/question/6258301
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