Sonar, originally an <span>acronym for SOund Navigation And Ranging
</span>a technique that uses sound<span> propagation.</span>
I cant find a article with that name? Are you sure its right?
Answer:1.5
Explanation:
Given
mass of first cart 
initial Velocity 
mass of second cart 
In the absence of External Force we can conserve momentum
Final kinetic Energy of two masses
Initial Kinetic Energy
Answer: only the third option. [Vector A] dot [vector B + vector C]
The dot between the vectors mean that the operation to perform is the "scalar product", alson known as "dot product".
This operation is only defined between two vectors, not one scalar and one vector.
When you perform, in the first option, the dot product of any ot the first and the second vectors you get a scalar, then you cannot make the dot product of this result with the third vector.
For the second option, when you perform the dot product of vectar B with vector C you get a scalar, then you cannot make the dot product ot this result with the vector A.
The third option indicates that you sum the vectors B and C, whose result is a vector and later you make the dot product of this resulting vector with the vector A. Operation valid.
The fourth option indicates the dot product of a scalar with the vector A, which we already explained that is not defined.
