Block 1, of mass m1 = 2.50 kg , moves along a frictionless air track with speed v1 = 27.0 m/s. It collides with block 2, of mass m2 = 33.0 kg , which was initially at rest. The blocks stick together after the collision.A. Find the magnitude pi of the total initial momentum of the two-block system. Express your answer numerically.B. Find vf, the magnitude of the final velocity of the two-block system. Express your answer numerically.C. what is the change deltaK= Kfinal- K initial in the two block systems kinetic energy due to the collision ? Express your answer numerically in joules.

Respuesta :

Answer:

a

The total initial momentum of the two-block system is  [tex]p_t = 67.5 \ kg \cdot m/s^2[/tex]

b

The magnitude of the final velocity of the two-block system [tex]v_f = 1.9014 \ m/s[/tex]

c

 the change ΔK=Kfinal−Kinitial in the two-block system's kinetic energy due to the collision is  

    [tex]\Delta KE =- 847.08 \ J[/tex]

Explanation:

From the question we are told that

    The mass of first  block  is [tex]m_1 = 2.50 \ kg[/tex]

      The initial velocity of first   block is [tex]u_1 = 27.0 \ m/s[/tex]

          The mass of second block is  [tex]m_2 = 33.0\ kg[/tex]

          initial velocity of second block is  [tex]u_2 = 0 \ m/s[/tex]

         

The magnitude of the of the total initial momentum of the two-block system is mathematically repented as

        [tex]p_i = (m_1 * u_1 ) + (m_2 * u_2)[/tex]

substituting values

        [tex]p_i = (2.50* 27 ) + (33 * 0)[/tex]

        [tex]p_t = 67.5 \ kg \cdot m/s^2[/tex]

According to the law of linear momentum conservation

        [tex]p_i = p_f[/tex]

Where  [tex]p_f[/tex] is the total final momentum of the system which is mathematically represented as

       [tex]p_f = (m_+m_2) * v_f[/tex]

Where [tex]v_f[/tex] is the final velocity of the system

      [tex]p_i = (m_1 +m_2 ) v_f[/tex]

substituting values

       [tex]67.5 = (2.50+33 ) v_f[/tex]

        [tex]v_f = 1.9014 \ m/s[/tex]

The change in kinetic energy is mathematically represented as

     [tex]\Delta KE = KE_f -KE_i[/tex]

Where [tex]KE_f[/tex] is the final kinetic energy of the two-body system  which is mathematically represented as

        [tex]KE_f = \frac{1}{2} (m_1 +m_2) * v_f^2[/tex]

substituting values

        [tex]KE_f = \frac{1}{2} (2.50 +33) * (1.9014)^2[/tex]

        [tex]KE_f =64.17 J[/tex]

While [tex]KE_i[/tex] is the initial kinetic energy of the two-body system

     [tex]KE_i = \frac{1}{2} * m_1 * u_1^2[/tex]

substituting values

       [tex]KE_i = \frac{1}{2} * 2.5 * 27^2[/tex]

        [tex]KE_i = 911.25 \ J[/tex]

So

    [tex]\Delta KE = 64.17 -911.25[/tex]

  [tex]\Delta KE =- 847.08 \ J[/tex]