- #1
coconut62
- 161
- 1
Question:
A heavy particle of mass m1, moving with speed u, makes a head-on collision with a light particle of mass m2, which is initially at rest. The collision is perfectly elastic, and m2 is very much less than m1, Describe the motion of the particles after the collision.
Answer:
Heavy particle's speed is practically unchanged; light particle moves with speed 2u, in same direction as the incident heavy particle.
My question:
Why must the speed of the light particle be 2u?
Lets say I take a 10kg particle colliding with a 0.1kg particle.
using Principle of Conservation of Momentum,
10u = 10Va + 0.1Vb
...then I take Va to be very small.
...
...
No matter how I see, I still cannot see why it's 2u :grumpy:
A heavy particle of mass m1, moving with speed u, makes a head-on collision with a light particle of mass m2, which is initially at rest. The collision is perfectly elastic, and m2 is very much less than m1, Describe the motion of the particles after the collision.
Answer:
Heavy particle's speed is practically unchanged; light particle moves with speed 2u, in same direction as the incident heavy particle.
My question:
Why must the speed of the light particle be 2u?
Lets say I take a 10kg particle colliding with a 0.1kg particle.
using Principle of Conservation of Momentum,
10u = 10Va + 0.1Vb
...then I take Va to be very small.
...
...
No matter how I see, I still cannot see why it's 2u :grumpy: