help with physics!?
Consider an elastic, head-on collision between
an object of mass m moving at speed v0 and
an object of mass 3 m, initially at rest. After the collision the mass m moves at a
velocity ~v1 and the mass 3 m at velocity of ~v2,
both along the original line of motion. What are the final velocities ~v1 and ~v2?
The sign on each will determine the direction
of the motion.
- NCSLv 71 month ago
For an elastic, head on collision, we know (from conservation of energy) that
v₀ = v₂ - v₁
so here v₁ = v₂ - v₀
Conserve momentum, substituting for v₁:
m*v₀ = m*(v₂ - v₀) + 3m*v₂ → → mass m cancels
v₀ = v₂ - v₀ + 3v₂
2v₀ = 4v₂
v₂ = v₀ / 2
You have to choices where this is true, so solve for v₁:
v₁ = v₀/2 - v₀ = -v₀/2
making #6 the correct choice.
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