Answer:
A
Step-by-step explanation:
We can use momentum and conservation of momentum equation to solve this problem. The equation would be:
[tex]m_1v_1+m_2v_2=(m_1+m_2)v_3[/tex]
m_1 is given as 2
v_1 is given as 3
m_2 is what we want
v_2 is 0 since they are sticking together after collision
v_3 is the final velocity at the resultant end, which is 1
Substituting and solving via algebra:
[tex]m_1v_1+m_2v_2=(m_1+m_2)v_3\\(2)(3)+m_2(0)=(2+m_2)(1)\\6+0=2+m_2\\6=2+m_2\\m_2=6-2=4[/tex]
Thus, mass of 2nd box is 4kg
Answer choice A is right
