Answer:
10 m/s
Explanation:
The problem can be solved by using the law of conservation of momentum: the initial momentum has to be equal to the final momentum, so we can write the following
\(p_i = p_f\)
\(m_1 u_1 + m_2 u_2 = (m_1 +m_2 )v\)
where
\(m_1 = 10,000 kg\) is the mass of the first car
\(u_1=30 m/s\) is the initial velocity of the first car
\(m_2 = 20,000 kg\) is the mass of the second car
\(u_2 = 0\) is the initial velocity of the second car
\(v\) is the final velocity of the two combined cars after the collision
Re-arranging the equation and substituting the numbers, we find
\(v=\frac{m_1 u_1 +m_2 u_2}{m_1+m_2}=\frac{(10,000)(30)-0}{10,000+20,000}=10 m/s\)
