Answer:[tex]10.71 m/s at angle of 75.96^{\circ}[/tex]
Explanation:
Given
Given two vehicles approach a right angle
Suppose one is traveling with towards north and other towards east
Ratio of their masses is [tex]\frac{m_1}{m_2}=\frac{1}{4}[/tex]
Both have a common velocity(u) of 13 m/s and v be the final velocity at an angle of [tex]\theta [/tex]w.r.t to east  after collision
after collision they both entangled thus
conserving Momentum in east i.e horizontal direction
[tex]m_1u=(m_1+m_2)v\cos \theta [/tex]---1
conserving momentum in North direction i.e. in vertical direction
[tex]m_2u=(m_1+m_2)v\sin \theta [/tex]---2
Divide 1 &2 Â we get
[tex]\frac{m_1}{m_2}=\frac{\cos \theta }{\sin \theta }[/tex]
[tex]\tan \theta =\frac{m_2}{m_1}[/tex]
[tex]\theta =75.96^{\circ}[/tex] w.r.t east
Thus v is given by
[tex]v\cos (75.96)=\frac{m_1\cdot u}{m_1+m_2}[/tex]
[tex]v\cos (75.96)=\frac{u}{1+4}[/tex]
[tex]v\cos (75.96)=\frac{13}{5}[/tex]
[tex]v=10.71 m/s[/tex]