The average lifetime of a pi meson in its own frame of reference (i.e., the proper lifetime) is 2.6 × 10−8 s. If the meson moves with a speed of 0.98c  , what is (a) its mean lifetime as measured by an observer on Earth, and (b) the average distance it travels before decaying, as measured by an observer on Earth? (c) What distance would it travel if time dilation did not occur?

The measured mean lifetime of an elementary particle when it is at rest in the lab is measured to be 2.6x10-8 s. If the particle is observed while traveling at a speed v=0.9 c with respect to the lab. What will be the value of the measured mean lifetime while the particle is moving?

12. (a) A particle is traveling through the Earth's atmosphere at a speed of 0.750c. To an earth bound observer, the distance it travels is 2.5km. How far does the particle travel in the particle's frame of reference? (b) Calculate the momentum of an electron traveling at a speed 0.985c? The rest mass of the electron is 9.11 X 10-31 kg.

A spaceship from another galaxy passes over the solar system directly above a radial line from the sunto the Earth. (We measure the distance between the Earth and the Sun to be 1.496 x 1011 m.) Anobserver standing on the Earth measures that the spaceship is approaching at 0.800c. The Earth-basedobserver also measures that it takes the spaceship 625 seconds to travel from the sun to Earth. Ignorethe relative motion of the Sun and Earth in this problem – their relative speed is only 0.001c, negligiblysmall compared to 0.800c.a) According to a scientist in the spaceship, the Earth-Sun distance is: ______8.9 x 10 ^10__________________b) According to a scientist in the spaceship, the time it takes her to travel the Earth-Sun distance is:_________374 s _______________c) What is the ratio of the kinetic energy to rest energy of the spaceship? KE/ER = _______0.667__________d) As the spaceship passed over the Sun, the alien scientist launched a probe toward Earth, traveling at0.200c relative to…

A particle's dynamics are considered "relativistic" when its velocity is a significant fraction of the speed of light.  For example, the mass of a moving particle seen by a stationary observer increases in proportion to the square root of 1/(1 - (v/c)2).  For typical speeds in the everyday world it is not noticeable, but take a fast moving fundamental particle and you may have apparent mass increases or changes in its lifetime as a consequence of time dilation.   Look at this factor for the electron you measured at 100 V in the glass globe. Pick the best answer.     The effect is less than 0.1 %.     The effect is around 1%.     The effect is around 10%.     The effect is a factor of 2 change in mass.

When pions are brought to rest their lifetime is 1.77´10-8 s. A beam of pions is produced in an accelerator and moves at a speed of 0.99c relative to the laboratory. After moving 39 m as measured in the la, half the pions have decayed. a) from the viewpoint of an observer in the lab frame and b) from an observer at rest in the frame of the moving pions that the two numerical results given in the problem for the half-life of the pions are consistent.

Suppose a cosmic ray colliding with a nucleus in the Earth's upper atmosphere produces a muon that has speed v = 0.99c. The muon then travels at constant speed and lives 1.5 μs as measured in the muon's frame of reference. (You can imagine this as the muon's internal clock.)Randomized Variablesv = 0.99 ct = 1.5 μs   Part (a)  How many kilometers does the muon travel according to an Earth-bound observer?  Part (b)  How many kilometers of the Earth pass by as viewed by an observer moving with the muon? Base your calculation on its speed relative to the Earth and its lifetime (proper time).

Consider a cosmic ray colliding with a nucleus in the Earth's upper atmosphere that produces a muon which has a velocity v = 0.916c. The muon then travels at constant velocity and lives 1.52 µs as measured in the muon's frame of reference. (You can imagine this as the muon's internal clock.) (a) How far (in km) does the muon in travel according to an Earth-bound observer? (b) How far (in km) does it travel as viewed by an observer moving with it? Base your calculation on its velocity relative to the Earth and the time it lives (proper time).

An unstable high-energy particle is created in the laboratory, and it moves at a speed of 0.992c. Relative to a stationary reference frame fixed to the laboratory, the particle travels a distance of 1.05 × 10-3 m before disintegrating. What is (a) the proper distance and (b) the distance measured by a hypothetical person traveling with the particle? Determine the particle's (c) proper lifetime and (d) its dilated lifetime. (a) Number   Units                                                             (b) Number   Units                                                             (c) Number   Units                                                             (d) Number   Units