Collisions and conservation laws
Collisions and conservation laws

Start this free course now. Just create an account and sign in. Enrol and complete the course for a free statement of participation or digital badge if available.

Free course

Collisions and conservation laws

7 Relativistic collisions

The high-energy collision experiments carried out at CERN, Brookhaven National Laboratory and other such facilities, involve particles that travel at speeds close to that of light. Under such circumstances the definitions of momentum and translational kinetic energy, that play such an important role in Newtonian mechanics, reveal certain shortcomings. It is still the case that translational kinetic energy is conserved in an elastic collision and that the momentum of an isolated system is always conserved, but the Newtonian expressions

bold p = m bold v and uppercase E sub trans = fraction 1 over 2 end m v squared

are now recognised as approximations, valid only at low speeds (i.e. at speeds much less than the speed of light), to more complicated expressions that work at any speed, up to the speed of light. The breakthrough that led to this realisation was the development of Einstein’s special theory of relativity in 1905. Here we shall quote a few of its well-established results concerning momentum and energy.


Take your learning further

Making the decision to study can be a big step, which is why you'll want a trusted University. The Open University has 50 years’ experience delivering flexible learning and 170,000 students are studying with us right now. Take a look at all Open University courses.

If you are new to University-level study, we offer two introductory routes to our qualifications. You could either choose to start with an Access module, or a module which allows you to count your previous learning towards an Open University qualification. Read our guide on Where to take your learning next for more information.

Not ready for formal University study? Then browse over 1000 free courses on OpenLearn and sign up to our newsletter to hear about new free courses as they are released.

Every year, thousands of students decide to study with The Open University. With over 120 qualifications, we’ve got the right course for you.

Request an Open University prospectus371