A particle moves along the x' axis of frame S' with velocity 0.21c. Frame S' moves with velocity 0.68c with respect to frame S. What is the speed of the particle with respect to frame S?

21. A particle moves along the x’ axis of frame S’ with velocity 0.21c. Frame S’ moves with velocity 0.68c with respect to frame S. What is the speed of the particle with respect to frame S? (____units)
22. Galaxy A is reported to be receding from us with a speed of 0.51c. Galaxy B, located in precisely the opposite direction, is also found to be receding from us at this same speed. What multiple of c gives the recessional speed an observer on Galaxy A would find for (a) our galaxy and (b) Galaxy B?
a. ______
b. ______
23. A spaceship, moving away from Earth at a speed of 0.974c, reports back by transmitting at a frequency (measured in the spaceship frame) of 81.3 MHz. To what frequency must Earth receivers be tuned to receive the report? (_____MHz)
24. How fast would you have to be moving for the 659 nm wavelength of a light source to appear as 588 nm to you, assuming that a relativistic calculation is not needed? (_____units)
25. How much work (in terms of MeV) must be done to increase the speed of an electron from rest to (a) 0.462c, (b) 0.981c, and (c) 0.9959c?
a. ______MeV
b. ______ MeV
c. ______ MeV
26. The mass of an electron is 9.109 381 88 x 10-31kg. Find (a) γ and (b) β for an electron with kinetic energy 23.5659 MeV.
a. ______units
b. ______ units
27. How much work (in terms of keV) must be done to increase the speed of an electron from (a) 0.26c to 0.28c and (b) from 0.92c to 0.94c? Note that the speed increase is 0.02c in both cases.
a. _____keV
b. _____keV
28. What is the nuclear mass density <ρm of (a) the fairly low-mass nuclide 56Fe and (b) the fairly high-mass nuclide 210At? Compare the two answers, with an explanation.What is the nuclear charge density ρq of (c)56Fe and (d)210At? Compare the two answers, with an explanation. a. ______units b. ______ units c. _____ units d. _____ units 29. What is the mass excess Δ1 of 1H (whose actual mass is 1.007825 u) in (a) atomic mass units and (b) MeV/c2? What is the mass excess Δn of a neutron (actual mass is 1.008665 u) in (c) atomic mass units and (d) MeV/c2? What is the mass excess Δ120 of 120Sn (actual mass is 119.902197 u) in (e) atomic mass units and (f) MeV/c2? a. _______units b. _______ MeV/c2 c. _______units d. _______ MeV/c2 e. _______units f. _______ MeV/c2 30. What is the binding energy per nucleon of the americium isotope