Nate the Skate was an avid physics student whose main non‑physics interest in life was high‑speed skateboarding. In particular, Nate would often don a protective suit of Bounce-Tex, which he invented, and after working up a high speed on his skateboard, would collide with some object. In this way, he got a gut feel for the physical properties of collisions and succeeded in combining his two passions\.\* On one occasion, the Skate, with a mass of 123 kg, including his armor, hurled himself against a 899 kg stationary statue of Isaac Newton in a perfectly elastic linear collision. As a result, Isaac started moving at 1.61 m/s and Nate bounced backward. What were Nate\'s speeds immediately before and after the collision? (Enter positive numbers.) Ignore friction with the ground. Before: ______ m/s After: _______ m/s *By the way, this brief bio of Nate the Skate is written in the past tense, because not long ago he forgot to put on his Bounce-Tex before colliding with the Washington Monument in a perfectly inelastic collision.

Respuesta :

Answer:

Explanation:

In the elastic collision , law of conservation of momentum will be followed.

Initial total momentum of the system

= 123 u + 0 = 123u ( u is initial velocity of nate)

Final momentum of the system

= 899 x 1.61 + 123 v

= 1447.39 + 123 v

For conservation of momentum

123u = 1447.39 + 123 v

For perfectly elastic collision

relative velocity of approach = relative velocity of separation

u - 0 = 1.61 - v

Putting this value of u in the previous equation

123 ( 1.61 -v ) = 1447.39 +123v

198.03 - 123v = 1447.39 +123v

- 1249.36 = 246 v

v =  - 5.078 m /s

u = 1.61 + 5.078

= 6.688 m /s

The   momentum conservation allows to find the result for Nate's velocity in the elastic collision are:

  • The initial velocity is: v₀ = 6.68 m / s
  • The final velocity is: [tex]v_f[/tex] = - 5.08 m / s

Parameters given

  • Nate's most with the skateboard m = 123 kg
  • The mass of the statue M = 899 kg.
  • The final velocity of the statue v =, 61 m / s
  • Elastic collision

To find

  • Skateboard speeds and Nate

The momentun is defined by the product of the mass and the velocity of a body, it is an isolated system this momentum is conserved.

          p = m v

Where the bold letters indicate vectors, p is the moment, m the mass and v the velocity

If we define the system formed by nate and the skateboard and the statue, the system is isolating and the forces during the collision are internal, therefore the momentum is conserved.

Initial instant. Before the Shock.

      p₀ = m v₀ + M 0

      p₀ = mv₀

Final moment. After the crash.

      [tex]p_f = m v_f + M v[/tex]  

The momentum is preserved.

       p₀ = [tex]p_f[/tex]

       m v₀ = m [tex]v_f[/tex]  + M v

They indicate that the collision is elastic, therefore the kinetic energy is conserved.

       K₀ = [tex]K_f[/tex]  

       ½ m v₀² = ½ m [tex]v_f^2[/tex]  + ½ M v²

       m v₀² = m [tex]v_f^2[/tex]  + M v²

Let's write our system of equations.

        mv₀ = m [tex]v_f[/tex] + M v

        m v₀² = m [tex]v_f^2[/tex]  + M v²

Let's solve

       m ([tex]v_f + \frac{M}{m}\ v[/tex] ) ² = m [tex]v_f^2[/tex]  + M v²

       [tex]v_f^2+ 2 \frac{M}{m} \ v \ v_f + (\frac{M}{m})^2 v^2 = v_f^2 + \frac{M}{m} \ v^2[/tex]

        [tex]v_f ( 2 \frac{M}{m} \ v) = \frac{M}{m} v^2 ( 1 - \frac{M}{m}) \\v_f = \frac{v}{2} \ ( 1- \frac{M}{m} )[/tex]

         

 Let's calculate

        [tex]v_f = \frac{1.61}{2} \ (1- \frac{899}{123} )[/tex]  

        [tex]v_f[/tex]  = -5.08 m / s

The negative sign indicates that the body goes in the opposite direction to the initial one.

Let's find the initial velocity.

        v₀ = [tex]v_f + \frac{M}{m} \ v[/tex]

        v₀ =  [tex]-5.08 \ + \frac{899}{123} \ 1.61[/tex]        

        v₀ = 6.69 m / s

In conclusion using the conservation of momentum we can find the result for Nate's velocity in the elastic collision they are:

  • The initial velocity is: v₀ = 6.68 m / s
  • The final velocity is:  [tex]v_f[/tex]  = - 5.08 m / s

Learn more here:  brainly.com/question/2141713

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