/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 35 (a) Using the relativistic expre... [FREE SOLUTION] | 91Ó°ÊÓ

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(a) Using the relativistic expression for total energy \(E\) and the magnitude \(p\) of the momentum of a particle, show that the two quantities are related by \(E^{2}=p^{2} c^{2}+\left(m c^{2}\right)^{2} \cdot(b)\) Use this expression to determine the linear momentum of a proton with a kinetic energy of \(1000 \mathrm{MeV}\).

Short Answer

Expert verified
The proton's momentum is approximately 1696 MeV/c.

Step by step solution

01

Recall the Relativistic Energy Equation

For a particle with rest mass \(m\), rest energy \(E_0 = mc^2\), momentum \(p\), and speed of light \(c\), the total energy is given by \(E = \sqrt{(pc)^2 + (mc^2)^2}\). Start with expressing \(E\) based on these parameters.
02

Rearrange Energy Equation

Square both sides of the equation from Step 1 to get: \(E^2 = (pc)^2 + (mc^2)^2\). This confirms the relationship: \(E^2 = p^2c^2 + (mc^2)^2\).
03

Use the Energy-Momentum Equation to find Momentum

Given the kinetic energy \(K = 1000 \text{ MeV}\) for a proton, the total energy is \(E = K + E_0 = 1000 \text{ MeV} + 938 \text{ MeV} = 1938 \text{ MeV}\) (since the rest energy of a proton \(E_0\) is 938 \text{ MeV}). Now use \(E^2 = p^2c^2 + (mc^2)^2\) to find \(p\).
04

Solve for Linear Momentum

Rearrange the equation \(E^2 = p^2c^2 + (mc^2)^2\) to solve for \(p\): \(p^2c^2 = E^2 - (mc^2)^2\). Plug in \(E = 1938 \text{ MeV}\) and \(mc^2 = 938 \text{ MeV}\) to get: \(p^2c^2 = 1938^2 - 938^2\). Compute \(p = \sqrt{\frac{1938^2 - 938^2}{c^2}}\).
05

Calculate the Numerical Value

Compute each term: \(1938^2 = 3757444\) and \(938^2 = 879844\), so \(1938^2 - 938^2 = 2877600\). Then, \(p = \frac{\sqrt{2877600}}{c}\). With \(1 \text{ MeV/c} = 5.344 \times 10^{-22} \text{ kg}\cdot\text{m/s}\), convert \(p\) to \text{MeV}/c: \(p \approx 1696 \text{ MeV}/c\).
06

Conclusion

The linear momentum of the proton with a kinetic energy of 1000 MeV is approximately 1696 MeV/c.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Total Energy Equation
The concept of total energy in the realm of relativity is an extension of classical physics, designed to include the effects that arise at high speeds, close to the speed of light. In relativistic physics, the total energy (\(E\)) of a particle is not just the sum of its kinetic and potential energy. The total energy includes both the kinetic energy it possesses due to its motion and its rest mass energy.
Using Einstein's famous equation, the rest energy (\(E_0\)) is given by \(E_0 = mc^2\), where \(m\) is the rest mass and \(c\) is the speed of light. Relativistic total energy is expressed as \(E = \sqrt{(pc)^2 + (mc^2)^2}\), where \(p\) stands for momentum.
This representation can be rearranged and squared to look like \(E^2 = p^2c^2 + (mc^2)^2\). This equation reveals how rest mass energy and momentum contribute to the total energy, offering a deeper understanding of the unity of energy and mass at relativistic speeds.
Momentum Calculation
In relativistic physics, momentum is intertwined with energy in ways that aren't evident in everyday experiences. It's crucial to calculate momentum with these extended ideas to capture all phenomena at high speeds.
The relativistic momentum (\(p\)) can be derived from the total energy equation \(E^2 = p^2c^2 + (mc^2)^2\). When calculating for momentum, one first rearranges to find:
  • \(p^2c^2 = E^2 - (mc^2)^2\)
  • \(p^2 = \frac{E^2 - (mc^2)^2}{c^2}\)
  • \(p = \sqrt{\frac{E^2 - (mc^2)^2}{c^2}}\)
For example, for a proton with a total energy of 1938 MeV and rest energy (mass energy) of 938 MeV, substituting these into the equation helps find the momentum with great precision. The result gives us an understanding of how energy is distributed in moving particles beyond classical expectations.
Kinetic Energy of Proton
Kinetic energy represents the extra energy a proton (or any other particle) has due to its motion. In relativistic terms, kinetic energy (\(K\)) is the energy a particle has when moving, minus its rest energy (\(E_0\)).
For a proton, the kinetic energy can be integrated into its total energy using the relation \(E = K + E_0\). In our scenario, a proton has a kinetic energy of 1000 MeV. The full total energy of this proton will then be the sum of 1000 MeV kinetic energy and its rest energy of 938 MeV, bringing it to 1938 MeV.
This energy plays a vital role in determining how the proton behaves, showing its increased dynamical properties due to the relativistic speeds. Adding to the overall energy helps illustrate how energy in particles at these scales is a blend of kinetic and intrinsic mass energies.

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Most popular questions from this chapter

In proton-antiproton annihilation, a proton and an antiproton (which has the same mass as the proton, but carries a negative charge) interact, and both masses are completely converted to electromagnetic radiation. Assuming that the particles are moving toward one another at a speed of 0.80 c relative to the laboratory reference frame before they annihilate, determine the total energy released in the form of radiation according to a laboratory technician.

A boat can make a round trip between two locations, \(A\) and \(B,\) on the same side of a river in a time \(t\) if there is no current in the river. (a) If there is a constant current in the river, the time the boat takes to make the same round trip will be (1) longer, (2) the same, (3) shorter. Why? (b) If the boat can travel with a speed of \(20 \mathrm{~m} / \mathrm{s}\) in still water, the speed of the river current is \(5.0 \mathrm{~m} / \mathrm{s},\) and the distance between points A and \(B\) is \(1.0 \mathrm{~km},\) calculate the round trip times when there is no current and when there is current.

A small airplane has an airspeed (speed with respect to air) of \(200 \mathrm{~km} / \mathrm{h}\). Find the time for the airplane to travel \(1000 \mathrm{~km}\) if there is (a) no wind, (b) a headwind of \(35 \mathrm{~km} / \mathrm{h},\) and \((\mathrm{c})\) a tailwind of \(35 \mathrm{~km} / \mathrm{h}\).

Suppose two black holes meet and "coalesce" into one larger black hole. If they each have the same mass \(M\) and Schwarzschild radius \(R,\) (a) express the single black hole's Schwarzschild radius as a multiple of \(R\). (b) express the average density of the single black hole in terms of the average density \((\rho)\) of each of the original black holes.

The distance to Planet X from Earth is 1.00 light-year. (a) How long does it take a spaceship to reach \(X\), according to the pilot of the spaceship, if the speed of the ship is \(0.700 c\) relative to \(X ?\) (b) How long does it take the ship to make the trip according to an astronaut already stationed on Planet \(X ?\) (c) Determine the distance between Earth and Planet \(X\) according to the pilot and according to the X-based astronaut and explain why the two answers are different.

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