A cart of mass 6.0 kg moves with a speed of 3.0 m/s towards a second stationary cart with a mass of 3.0 kg. The carts move on a frictionless surface and when the carts collide they stick together. What is the ratio of the initial kinetic energy of the two-cart system to the final kinetic energy of the two-cart system?

Respuesta :

Answer:1.5

Explanation:

Given

mass of first  cart [tex]m_1=6 kg[/tex]

initial Velocity [tex]u_1=3 m/s[/tex]

mass of second cart [tex]m_2=3 kg[/tex]

[tex]u_2=0 m/s[/tex]

In the absence of External Force we can conserve momentum

[tex]m_1u_1+m_2u_2=(m_1+m_2)v[/tex]

[tex]v=\frac{m_1u_1+m_2u_2}{m_1+m_2}[/tex]

[tex]v=\frac{6\times 3+3\times 0}{6+3}[/tex]

[tex]v=2 m/s[/tex]

Final kinetic Energy of two masses

[tex]K.E._2=\frac{1}{2}(m_1+m_2)v^2[/tex]

[tex]K.E._2=\frac{1}{2}\cdot (3+6)\cdot (2)^2[/tex]

[tex]K.E._2=18 J[/tex]

Initial Kinetic Energy

[tex]K.E._1=\frac{1}{2}m_1u_1^2+\frac{1}{2}m_2u_2^2[/tex]

[tex]K.E._1=\frac{1}{2}6\times 3^2+0[/tex]

[tex]K.E._1=27 J[/tex]

[tex]ratio =\frac{K.E._1}{K.E._2}=\frac{27}{18}=1.5[/tex]

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