Question

a magnetic hockey puck (0.40 kg) hits another hockey puck (0.40 kg) at rest and both travel together to the right at 8.0 m/s. how fast was the first hockey puck initially moving? m/s 8.0 16 6.4

Explanation:

Step1: Aplicar la ley de conservación de la cantidad de movimiento

$$m_1v_1 + m_2v_2=(m_1 + m_2)v_{final}$$
Donde \(m_1 = 0.40\space kg\), \(v_2=0\space m/s\) (el segundo disco está en reposo), \(m_2 = 0.40\space kg\) y \(v_{final}=8.0\space m/s\)

Step2: Sustituir los valores en la ecuación

$$0.40\times v_1+0.40\times0=(0.40 + 0.40)\times8.0$$
$$0.40v_1=0.80\times8.0$$

Step3: Resolver para \(v_1\)

$$v_1=\frac{0.80\times8.0}{0.40}$$
$$v_1 = 16\space m/s$$

Answer:

16