Well, the diameter of a circle is simply a length, so your measurement will have units of length. We just have to find an answer that has only units of length.
A). gram, second . . . mass and time. That can't be it.
B). kilogram, ampere . . . mass and current. That can't be it.
C). centimeter, meter . . . both lengths. This one is looking good.
D). candela, mole . . . light intensity and some chemical thing. That can't be it.
So it can't be anything else on this list but <em>C</em> .
Answer: (d)
Explanation:
Given
Mass of object 
Speed of object 
Mass of object at rest 
Suppose after collision, speed is v
conserving momentum
Initial kinetic energy
Final kinetic energy
So, it is clear there is decrease in kinetic energy . Thus, energy decreases and velocity becomes 2 m/s.
If the object's kinetic energy is zero, then due to in multiplication factor, it's momentum will also be equal to zero 'cause the velocity of the object must be Nil
In short, Your Answer would be: "Zero"
Hope this helps!
