Question

problem 1
a 10 kg dog runs at 5 m/s to the right. a 20 kg dog runs at 4 m/s to the
left. what is the total momentum (p) of the two dog system? let the right
be positive.

Explanation:

Step1: Calculate momentum of first dog

Momentum formula is \(p = mv\). For the first dog, \(m_1=10\space kg\) and \(v_1 = 5\space m/s\). So \(p_1=m_1v_1=10\times5 = 50\space kg\cdot m/s\)

Step2: Calculate momentum of second dog

For the second dog, \(m_2 = 20\space kg\) and \(v_2=- 4\space m/s\) (left - negative). So \(p_2=m_2v_2=20\times(-4)=-80\space kg\cdot m/s\)

Step3: Calculate total momentum

Total momentum \(p = p_1 + p_2\). Substitute values: \(p=50+(-80)=- 30\space kg\cdot m/s\)

Answer:

\(-30\space kg\cdot m/s\)