Question

in a closed system, an object with a mass of 10 kg moves at a velocity of 5.4 m/s. it collides with a second object that has a mass of 12 kg and that is moving in the opposite direction with a velocity of 3.5 m/s. what is the total momentum of the system after the collision? (1 point)

66 kg - m/s

42 kg - m/s

54 kg - m/s

12 kg - m/s

Explanation:

Step1: Define momentum formula

Momentum $p = mv$. Let the first - object's velocity be positive, so the second - object's velocity is negative.

Step2: Calculate momentum of first object

$p_1=m_1v_1$, where $m_1 = 10\ kg$ and $v_1=5.4\ m/s$. So $p_1=10\times5.4 = 54\ kg\cdot m/s$.

Step3: Calculate momentum of second object

$p_2=m_2v_2$, where $m_2 = 12\ kg$ and $v_2=- 3.5\ m/s$. So $p_2=12\times(-3.5)=-42\ kg\cdot m/s$.

Step4: Calculate total initial momentum

In a closed system, total momentum before collision equals total momentum after collision. $p_{total}=p_1 + p_2$. So $p_{total}=54+( - 42)=12\ kg\cdot m/s$.

Answer:

12 kg - m/s