Chapter 7: Problem 12
Obtain the relation between the total kinetic energy in the CM and Lab frames. Discuss the limiting cases of very large and very small mass for the target.
Chapter 7: Problem 12
Obtain the relation between the total kinetic energy in the CM and Lab frames. Discuss the limiting cases of very large and very small mass for the target.
All the tools & learning materials you need for study success - in one app.
Get started for freeTwo particles of masses \(m_{1}\) and \(m_{2}\) are attached to the ends of a light spring. The natural length of the spring is \(l\), and its tension is \(k\) times its extension. Initially, the particles are at rest, with \(m_{1}\) at a height \(l\) above \(m_{2} .\) At \(t=0, m_{1}\) is projected vertically upward with velocity \(v\). Find the positions of the particles at any subsequent time (assuming that \(v\) is not so large that the spring is expanded or compressed beyond its elastic limit).
An experiment is to be designed to measure the differential cross-section for elastic pion-proton scattering at a CM scattering angle of \(70^{\circ}\) and a pion CM kinetic energy of \(490 \mathrm{keV}\). (The electron-volt \((\mathrm{eV})\) is the atomic unit of energy.) Find the angles in the Lab at which the scattered pions, and the recoiling protons, should be detected, and the required Lab kinetic energy of the pion beam. (The ratio of pion to proton mass is \(1 / 7\).)
An unstable particle of mass \(M=m_{1}+m_{2}\) decays into two particles of masses \(m_{1}\) and \(m_{2}\), releasing an amount of energy \(Q .\) Determine the kinetic energies of the two particles in the CM frame. Given that \(m_{1} / m_{2}=4, Q=1 \mathrm{MeV}\), and that the unstable particle is moving in the Lab with kinetic energy \(2.25 \mathrm{MeV}\), find the maximum and minimum Lab kinetic energies of the particle of mass \(m_{1}\).
Write down the equations of motion for a pair of charged particles of equal masses \(m\), and of charges \(q\) and \(-q\), in a uniform electric field \(\boldsymbol{E}\). Show that the field does not affect the motion of the centre of mass. Suppose that the particles are moving in circular orbits with angular velocity \(\omega\) in planes parallel to the \(x y\)-plane, with \(\boldsymbol{E}\) in the \(z\)-direction. Write the equations in a frame rotating with angular velocity \(\omega\), and hence find the separation of the planes.
The parallax of a star (the angle subtended at the star by the radius of the Earth's orbit) is \(\varpi\). The star's position is observed to oscillate with angular amplitude \(\alpha\) and period \(\tau\). If the oscillation is interpreted as being due to the existence of a planet moving in a circular orbit around the star, show that its mass \(m_{1}\) is given by \(\frac{m_{1}}{M_{\mathrm{S}}}=\frac{\alpha}{\varpi}\left(\frac{M \tau_{\mathrm{E}}}{M_{\mathrm{S}} \tau}\right)^{2 / 3}\) where \(M\) is the total mass of star plus planet, \(M_{\mathrm{S}}\) is the Sun's mass, and \(\tau_{\mathrm{E}}=1\) year. Evaluate the mass \(m_{1}\) if \(M=0.25 M_{\mathrm{S}}, \tau=16\) years, \(\varpi=0.5^{\prime \prime}\) and \(\alpha=0.01^{\prime \prime} .\) What conclusion can be drawn without making the assumption that the orbit is circular?
What do you think about this solution?
We value your feedback to improve our textbook solutions.