How can I solve for the mass of the first car in an elastic collision problem?

In summary, an elastic collision is a collision between two objects where there is no loss of kinetic energy, and the total momentum is conserved. The final velocities can be calculated using the equations v1 = (m1 - m2)v1i + 2m2v2i / (m1 + m2) and v2 = 2m1v1i - (m1 - m2)v2i / (m1 + m2). In contrast, an inelastic collision involves a loss of kinetic energy and possible deformation of the objects. To solve for the velocities algebraically, these equations can be used by plugging in the known values for masses and initial velocities.
  • #1
tony873004
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In an elastic collision problem, I'm supposed to solve for the mass of the 1st car (m1). I get stuck here. How do I re-write this to solve for m1?

[tex]u_2=\frac{2*m_1v_1}{m_1+m_2}[/tex]
 
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  • #2
Thats the equation for an inelastic collision, but

[tex] u_2m_1+u_2m_2-2m_1v_1 = 0 [/tex]

[tex] u_2m_1 - 2m_1v_1 = -u_2m_2 [/tex]

[tex] m_1(u_2 - 2v_1)= -u_2m_2 [/tex]

[tex] m_1 = \frac{-u_2m_2}{u_2-2v_1} [/tex]
 
  • #3
Thanks, whozum. That worked !
 

1. What is an elastic collision?

An elastic collision is a type of collision between two objects where there is no loss of kinetic energy. This means that the total kinetic energy before and after the collision is the same.

2. How is the momentum conserved in an elastic collision?

In an elastic collision, the total momentum of the system before and after the collision is conserved. This means that the sum of the momenta of the two objects before the collision is equal to the sum of the momenta after the collision.

3. What is the equation for calculating the final velocities in an elastic collision?

The equation for calculating the final velocities in an elastic collision is:
v1 = (m1 - m2)v1i + 2m2v2i / (m1 + m2)
v2 = 2m1v1i - (m1 - m2)v2i / (m1 + m2)
where m is the mass of the object and vi is the initial velocity before the collision.

4. What is the difference between an elastic collision and an inelastic collision?

In an elastic collision, the total kinetic energy is conserved, while in an inelastic collision, some kinetic energy is lost. In an inelastic collision, the objects may stick together or deform, while in an elastic collision, they bounce off each other without any deformation.

5. How can I solve for the velocities in an elastic collision algebraically?

To solve for the velocities in an elastic collision algebraically, you can use the equations v1 = (m1 - m2)v1i + 2m2v2i / (m1 + m2) and v2 = 2m1v1i - (m1 - m2)v2i / (m1 + m2). Plug in the known values for the masses and initial velocities, and solve for the final velocities.

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