A 4-kg ball traveling westward at 25 m/s hits a 15-kg ball at rest. The 4-kg ball bounces east at 8.0 m/s. What is the speed and direction of the 15-kg ball? What is the impulse of the second ball?

Respuesta :

Given:

The mass of the first ball is,

[tex]m_1=4\text{ kg}[/tex]

The initial velocity of the first ball towards West is,

[tex]u_1=25\text{ m/s}[/tex]

The mass of thr second ball is,

[tex]m_2=15\text{ kg}[/tex]

the second object is initially at rest.

The final velocity of the first ball is,

[tex]v_1=-8.0\text{ m/s}[/tex]

we are taking West as positive.

Applying momentum conservation principle we can write,

[tex]m_1u_1+m_2\times0=m_1v_1+m_2v_2[/tex]

Substituting the values we get,

[tex]\begin{gathered} 4\times25+0=4\times(-8.0)+15\times v_2 \\ v_2=\frac{100+32}{15} \\ v_2=8.8\text{ m/s} \end{gathered}[/tex]

THe final velocity of the second ball is towards East and the magnitude is 8.8 m/s.

The impulse of the Second ball is,

[tex]\begin{gathered} I=m_2v_2-m_2\times0 \\ =15\times8.8 \\ =132\text{ kg.m/s} \end{gathered}[/tex]