9.3.2 Relativistic Energy Flashcards
Relativistic Energy
- The relativistic definition of kinetic energy: .
- An object at rest has energy due to its mass, or rest energy: .
- The total energy of an object is the sum of its kinetic and rest energies: . This equation can also be written as , where m is the relativistic mass of the object in question. According to this equation, mass and energy are intimately related—one can be converted into the other, and vice versa.
Which of the following is the relativistic definition of kinetic energy?
gm0c^2 - m0c^2
The relativistic formula for kinetic energy is gm0c^2 - m0c^2. Which of the following denotes the kinetic energy when an object is at rest?
0
Evaluate the following as true or false. The relativistic formula for kinetic energy is gm0c^2 - m0c^2. As v become small compared to c, this relationship would reduce to the non relativistic definition (1/2)mv^2
true
A particle has a rest energy E0 equal to 135 MeV (1.35*10^8 eV). Which of the following is the rest mass (in kg) of the particle?
2.4*10^-28 kg
A photon (light particle) has zero rest mass. Which of the following statements about a photon is incorrect?
It total energy is zero.
Evaluate the following as true or false. By combining the relativistic formulas for energy and momentum, an important relationship, E^2 = (pc)^2 + (m0c^2)^2, is derived. If the momentum of a particle is zero, then its kinetic energy is not necessarily zero.
false
The postulates of relativity give a single formula for the total energy of an object, E = mc^2. This relationship can be expressed in several equivalent forms. Which of the following is not correct?
E = sqrt(1 - v^2/c^2(m0c^2)
Which of the following is invariant?
All of the above.
Consider a ball with a rest mass of 1 g. Which of the following is the energy equivalent of the ball’s mass based on the special theory of relativity?
9*10^13 J
