# special relativity

posted by .

A projectile of rest mass M1, total energy E1, and momentum p1, is directed at a stationary target of mass m2. Find the the velocity of the centre-of-momentum frame .

• special relativity -

The total energy of a system is given by:

E = gamma m c^2

The total momentum is:

p = gamma m v

The ratio p/E is thus:

p/E = v/c^2

So, if we know the energy and momentum of a system, we know the velocity.

For the given system, the energy is:

E = E1 + m2 c^2

The momentum is

p = p1

Therefore:

v = c^2 p/E = c^2 p1/(E1 + m2 c^2)

## Respond to this Question

 First Name School Subject Your Answer

## Similar Questions

1. ### Science

Two masses of 20 and 10 kg are moving in the same direction and one directly behind the other. The 20-kg mass is behind and moving at 10m/s and the other is moving at 5m/s. The masses collide and after the collison, the 20kg mass moves …
2. ### physics

write down in terms of the mass m and the velocity v of the body, expressions for i) momentum ii) the kinetic energy use your answer to (b) to help calculate the mass and the velocity of the ball momentum is mass*velocity Kinetic energy …
3. ### physics, please reply.

block 1 of mass 1 slides from rest along a frictionless ramp from height h=2.50m and then collides with stationary block 2, which has mass2=2.00 m1. After the collision, block 2 slides into a region where the coefficient of kinetic …
4. ### Physics

Ok, so this probem is kinda complicated, so ask me if you need clarification. This problem deals with Impulse and Momentum. There are two balls hanging vertically from a horizontal plane. Ball A is pulled back and is set up to strike …
5. ### physics

work & energy homework problems: please help me =] my teacher is bad a teaching how to do stuff =/ 1)A 5.000kg plastic ball moves with a velocity of 10.00 m/s x. It collides with a second plastic ball of mass of 10.00kg at rest. The …
6. ### special relativity

A photon of energy E collides with a stationary particle of rest mass m0 and is absorbed by it. what is the velocity of the resulting composite particle ?
7. ### modern physics - relativity

A photon of energy E collides with a stationary particle of rest mass m0 and is absorbed by it . (A) what is the velocity of resulting composite particle ?
8. ### Physics

Two masses, m1 = 2.0 kg and m2 = 3.3 kg, are moving in the xy-plane. The velocity of their center of mass and the velocity of mass 1 relative to mass 2 are given by the vectors vcm = (−1,+2.2) m/s and vrel = (+4.5, +1.0) m/s. …
9. ### Physics: Collison/Momentum Problem

A 15 kg mass, moving east at 5 m/s, collides elastically with another 10 kg mass, moving west at 1 m/s. After the collision, the larger mass moves off with a velocity of 3 m/s. What is the final velocity of the smaller mass?
10. ### phys3

A projectile of mass 2.0 kg approaches a stationary target body at 4.9 m/s. The projectile is deflected through an angle of 59.8° and its speed after the collision is 2.8 m/s. What is the magnitude of the momentum of the target body …

More Similar Questions