# momentum

posted by .

do gamma rays carry momentum? i thought they don't because they don't have mass so mv=0 but my frend says even tho they don't have mass they still carry momentum. how does this make sense? please help.

• momentum -

Photons in general carry momentum so any electromagnetic wave has momentum associated with it despite its lick of rest mass in the classical sense. If a photon hits something, it moves it.

E = energy of photon = m c^2 = h f where c is velocity of light and h is plank constant and f is the frequency
Of course we know classical rest mass m is zero but that does not prove there is no energy, m c^2 at the velocity of light.
then m c = momentum p
but m c = E/c
so p = E/c
but E = h f
so
momentum p = h f /c
but f/c = 1/Tc = 1/Lambda
where T is period and Lambda is wavelength
so
p = h/Lambda

## Similar Questions

1. ### Physics

A child throws a snowball at a tree and it sticks to the tree. Does this motion defy the Law of Conservation of Momentum?
2. ### 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. …
3. ### 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?
4. ### Physics ~MOMENTUM~

a) what is the momentum of a 4.6 kg baseball moving at 1.4 m/s?
5. ### Physics

I think I chose the correct answer. In a closed system, two carts have a compressed spring between them. One of the carts has a total mass, including its contents, of 2.0 kg, and the other has total mass of 1.0 kg. Which cart experiences …
6. ### physics

Explain how it is possible for a motorcycle (mass = 250 kg) to have the same momentum as a locomotive engine (mass = 2,500 kg) i though momentum was directly proportional to mass so the more mass the more the momentum?
7. ### College

Two motorcycles of equal mass collide at a 90 intersection. If the momentum of motorcycle A is 450 kg km/h west and the momentum of motorcycle B is 725 kg km/h south, what is the magnitude of the resulting momentum of the final mass?
8. ### Physics

1.Two motorcycles of equal mass collide at a 90 degree intersection. If the momentum of motorcycle A is 450 kg km/h west and the momentum of motorcycle B is 725 kg km/h south, what is the magnitude of the resulting momentum of the …
9. ### Physics

4. Two vehicles of equal mass collide at a 90° degree intersection. If the momentum of vehicle A is 1.20x10^5 kg km/h east and the momentum of vehicle B is 8.50x10^4 kg km/h north, what is the resulting momentum of the final mass?
10. ### AP Physics 1 Momentum

I have a select-multiple question, and I am not sure about everything and I only get one try in my online class...would really appreciate if you could please explain which to select: What is true about momentum value?

More Similar Questions