Exam 27: Quantum Physics Blackbody Radiation and Plancks Hypothesis: Part A

A tuning fork has a frequency of 400 Hz and hence a period of 2.50 × 10−³ s.If the tuning fork is in an inertial frame of reference moving by the observer at speed of 0.680c,what is the frequency of the fork as measured by the observer? (Assume that measurements are strictly by optical means and that the speed of sound waves in air is not pertinent here. )

When a four-megaton nuclear bomb is exploded,approximately 18 × 10¹⁵ J of energy is released.How much mass would this represent in a mass-to-energy conversion? (c = 3.00 × 10⁸ m/s)

If astronauts could travel at v = 0.90c,we on Earth would say it takes (4.2/0.90)= 4.7 years to reach Alpha Centauri,4.2 lightyears away.The astronauts disagree.How much time passes on the astronaut's clocks?

A particle of mass m is moving at speed ​v​ = ​c​/2.What is its momentum?

At what speed is the momentum of an object triple that found classically?

An electron of mass 9.11 × 10−³¹ kg moves with a speed of 0.800c.What is its momentum? (c = 3.00 × 10⁸ m/s)

A meterstick moving in a direction parallel to its length appears to be only 60.0 cm long to an observer.What is the meterstick's speed relative to the observer? (c = 3.00 × 10⁸ m/s)

What is the speed of a particle having a kinetic energy equal to its rest energy?

A nuclear reaction,which gives off a total of 2.0 × 10¹⁶ J of energy,expends how much mass in the process? (c = 3.00 × 10⁸ m/s)

A ground observer measures the period of a pendulum moving as a part of an inertial frame of reference to be 2.30 s as the inertial frame moves by at a velocity of 0.800c.What would the observed period be of the same pendulum if its inertial frame were at rest with respect to the observer?

A proton with mass 1.67 × 10−²⁷ kg moves in an accelerator with a speed of 0.600c.What is its total energy? (c = 3.00 × 10⁸ m/s)

In an X-ray tube,high-speed electrons are slammed into a lead target,giving off X-rays.If the electrons are accelerated from rest through a potential difference of 100,000 volts,what speed do they have when they strike the target? (q_e = 1.6 × 10−¹⁹ C,m_e = 9.11 × 10−³¹ kg,and c = 3.00 × 10⁸ m/s)

Muons at speed 0.9994c are sent round and round a circular storage ring of radius 1500 m.If a muon at rest decays into other particles after an average T = 2.2 × 10−⁶ s,how many trips around the storage ring do we expect the 0.9994c muons to make before they decay?

A muon formed high in Earth's atmosphere travels at a speed 0.9900c for a distance (as we see it)of 9200 m before it decays.How far does the muon travel as measured in its frame?

At what speed must an object be moving in order that it has a kinetic energy 2.50 times its rest energy? (c = 3.00 × 10⁸ m/s)

The mass of a proton at rest is m.If the proton is moving so fast that its total energy is four times its rest energy,then what is the kinetic energy of the proton?

How fast would a rocket have to move past a ground observer if the latter were to observe a 3.0% length shrinkage in the rocket length? (c = 3.00 × 10⁸ m/s)

The period of a pendulum is 2.0 s in a stationary inertial frame of reference.What is its period when measured by an observer moving at a speed of 0.80c with respect to the inertial frame of reference?

As measured from the Earth,a spacecraft is moving at speed 0.80c toward another spacecraft moving at speed 0.60c in the same direction,i.e. ,the first spacecraft is catching up with the second spacecraft.What is the speed of the first spacecraft as viewed from the second spacecraft?

An astronaut is traveling at a high rate of speed from the Earth to a distant star system.Observers here on Earth note the relativistic effect that the astronaut's clocks run slow.What relativistic effect,if any,does the astronaut observe?