A billiard ball of mass m moving with speed v1=1 m/s collides head-on with a second ball of mass 2m which is at rest. What is the velocity of the ball of mass 2m after the collision?

The velocity of mass 2m is  

Explanation:

From the question w are told that

     The mass of the billiard ball A is =m

     The initial speed  of the billiard ball A = =1 m/s

    The mass of the billiard ball B is = 2 m

    The initial speed  of the billiard ball  B = 0

Let the final speed  of the billiard ball A  =

Let The finial speed  of the billiard ball  B =

      According to the law of conservation of Energy

              Substituting values  

Multiplying through by

    According to the law of conservation of Momentum

    Substituting values

Multiplying through by

making subject of the equation 2

Substituting this into equation 1

Multiplying through by

the components of a vector are the parts of the vectors that are to each other.

b perpendicular

3. dark matter

empty space could also be a simple vacuum