You are in a windowless car in an exceptiotxs mzz s -:mxywe7q3-:i( ip3nally smooth train moving at constant velocity. Is there any physical experimewt:ipm( :mx sy3-sz3e- iz x7qnt you can do in the train car to determine whether you are moving? Explain. ----待选择----yesno 

You might have had the exp27ih2mcmco hfru().n erience of being at a red light when, out of the corner of your eye, you see the car beside you creep forward. Instinctively you stomp on the brake pedal, thinking that you are rolling backward. What does this say about absolute aci()h2o.f hmnc 72rm und relative motion?

A worker stands on top of a moving railroad car, and throws *vr-7gjucy,+ j.e-apd lkf5 ba heavy ball straight up (from his point of view). Ignoring air resistancpf7 ,dv-ku5a*jl brgc. yej-+ e, will the ball land on the car or behind it?

Does the Earth really go around the Sun? Or is it also valid to saygtah oqtlc* g::;q zt0h4i09 a that the Sun goes around the Earth? Discuss in view of the first pral 0t 4h ;90zaqto:gqtgc*:i hinciple of relativity (that there is no best reference frame). Explain.

If you were on a spaceshi8 y 3ji1 wjkpii4c3xz9p traveling at 0.5c away from a star, at what speed would the starlig3 kyx8j19wcipz3i4j i ht pass you?

The time dilation effect is sometimes expdnrp;.r+9thg ulttek 1,4q:m ressed as “moving clocks run slowly.” Actually, this effect has nothing to do with motion affecting the functioning of clocks. What theqr ug.9:4 lrtt;pd kn1+m,then does it deal with?

Does time dilation mean u7:htk dosyx6/ q./ lathat time actually passes more slowly in moving reference frames or thak .suqh6 ot/dl :/xy7at it only seems to pass more slowly?

A young-looking woman astronaut has just arrived home from a long trip. Shezbdv+oo k 6v16 rushes up to an old gray-haired man and in the ensuing conversation refers to hd61 6+bov vkzoim as her son. How might this be possible?

If you were traveling away from Earth at speed 0.5c, would you notice a change irt e/z 3 eoauf1.jf34(byk 3qjn your heartbeat? Would your mass, height, or waistline change? What would observer/uktyffao31.3 jqj(ere 34b zs on Earth using telescopes say about you?

Do time dilation and length contramroo/i /g.5bbzg5x xu6x7 ,h yction occur at ordinary speeds, say $90 \, \text{km/h}$?

Suppose the speed of light were infinite. What would happen to the relativispjlu--.ytnb1 6 b mg d4/c(vrc sts;b0tic predictions of length contraction and tit (ry-gtu; 1v/4cb0 6jsdnp.b s b-clmme dilation?

Discuss how our everyday lives would be different if the s8,w8;hxmr*1om ohvnu peed of light were only m1*;oox8umn rh vhw8,$25 \, \text{m/s}$.

Explain how the length cla5f io7a rot7-. nkk.s;pm+nontraction and time dilation formulas might be used to indicater. n i+-;5po.tmk7 7sla oknaf that c is the limiting speed in the universe.

The drawing at the start of this Cyxlej p* 7qn96hapter shows the street as seen by Mr Tompkins, for whom the speedql7xjn9 ep*6y of light is $c=20 \, \text{mi/h}$. What does Mr Tompkins look like to the people standing on the street? Explain.

  An electron is limited to travel at spee9t ;.au)3ffhp y kxz2vds less than c. Does this put an upper limit on the momentum of an electron? If so, what is this upper limit? If not, explaixu; .hfaky)z 9tpf2v 3n. ----待选择----yesno 

  Can a particle of nonzero rerqd* 2xt7kq c5st mass attain the speed of light? ----待选择----yesno 

  Does the equation $E=mc^2$ conflict with the conservation of energy principle? Explain. ----待选择----yesno 

  If mass is a form of energy, does this mean that a lo5g:n eiy/vz.l d0w5spring has more mass when compressed than whenvd:lg0 eywo5iz5.n /l relaxed? ----待选择----yesno 

It is not correct to say that "matter can neither be created nor destrhi+i;8dc8f-ol 0svgd ;bxif4oyed." What must we say instef0hdi vl- 8b s;8fiox+4c; digad?

  Is our intuitive notion that velocities simply add, as we did in/mvpwjk k+fw 3,r6 ,yo Section 3–8, completely wrongrm k6vwo /,pw fj3,y+k? ----待选择----yesno 

  A spaceship passes you at a speed of 0.750c. You measu s ; m:hset1vh4+;nxwcre its length to be 28.2 m. How lom xt;;:hcs4hws 1nev+ng would it be when at rest? $L_0$ =    m

  A certain type of element01p w5 g, z:ajpjhxg6sui0ce8ary particle travels at a speed of $2.70 \times 10^8 \, \text{m/s}$. At this speed, the average lifetime is measured to be $4.76 \times 10^{-6} \, \text{s}$. What is the particle's lifetime at rest?
$\Delta t$ =    $ \times 10^{-6} \, \text{s}$

  Lengths and time intervals depend on the factor q r y*peqi8qmp.99,r hxl03eb $\beta = \frac{1}{\sqrt{1 - v^2/c^2}}$ according to the theory of relativity. Evaluate this factor $\beta$ for speeds of:
(a) $v = 20000 \, \text{m/s}$ (typical speed of a satellite); $\beta =$  
(b) $v=0.10c \;\; \beta =$  
(c) $v=0.20c \;\; \beta =$  
(d) $v=0.95c \;\; \beta =$  
(e) $v=0.98c \;\; \beta =$  
(f) $v=0.999c \;\; \beta =$  

  If you were to travel to a star 125 lightj ioe:.:s:6r9mdbdbiz:t fz.dq1w t)-years from Earth at a speed of $2.50 \times 10^8 \, \text{m/s}$, what would you measure this distance to be? L =    ly

  What is the speed of a pion if its average lifetime is measured to b4 e6+ dcz+xe2pwp*g3ozj; fxi e $4.10 \times 10^{-8} \, \text{s}$? At rest, its average lifetime is $2.60 \times 10^{-8} \, \text{s}$. v =    c

  In an Earth reference frame, a star egc7v 9g,n;v.rhx- ak is 82 light-years away. How fast would you have to travel so that to you the distance would be only 35 light-ye.-kae ,9xgvnv 7h cg;rars? v =    c

  Suppose you decide to travel to a stl *) p7be(us-dey bx y75gbbe*0cx9lxar 85 light-years away at a speed that tells you the distance is -5l eg0xbydbec b(7xe*9 y xupl)b*7s only 25 light-years. How many years would it take you to make the trip? t =    y

  At what speed $v$ will the length of a 1.00-m stick look 10.0% shorter (90.0 cm)? v =    c

  Escape velocity from the mf +odz 58(.n neiqzo(Earth is $11.2 \times 10^3 \, \text{m/s}$. What would be the percent decrease in length of a 95.2-m-long spacecraft traveling at that speed? L =    $ \times 10^{-8}\%$

  At what speed $v$ do the relativistic formulas for (a) length and (b) time intervals differ from classical values by 1.00%? (This is a reasonable way to estimate when to do relativistic calculations rather than classical.) v =    c

  Suppose a news report stated that so1,. dunww s4ktarship Enterprise had just returned from a 5-year voyage while traveling at 0.84c w.usd kwn14o,.
(a) If the report meant 5.0 years of Earth time, how much time elapsed on the ship? $\Delta t_0$ =    yr
(b) If the report meant 5.0 years of ship time, how much time passed on Earth? $\Delta t$ =    yr

  A certain star is 10.6 light-years away. Hod3 n lw99sdo5,uc*c pww long would it take a spacecraft traveling 0.n9d5pccw u 9* lsdow,3960c to reach that star from Earth, as measured by observers:
(a) on Earth, $t_{earth}$ =    yr
(b) on the spacecraft? $\bigtriangleup t_0$ =    yr
(c) What is the distance traveled according to observers on the spacecraft? L =    ly
(d) What will the spacecraft occupants compute their speed to be from the results of (b) and (c)? v =    c

  A friend speeds by you in /mzoic; f2n1mher "Ferrari" spacecraft at a speed of 0.660c. It is measured in your frame to be 4.80 m long anmf1ncizm2o ;/ d 1.25 m high.
(a) What will be its length and height at rest?
$L_0$ =    m
the rest height is    m
(b) How many seconds would you say elapsed on your friend's watch when 20.0 s passed on yours? $\bigtriangleup t_0$ =    s
(c) How fast did you appear to be traveling according to your friend?    c
(d) How many seconds would she say elapsed on your watch when she saw 20.0 s pass on hers?   s

  How fast must an average piond6;z wy9gqh*(/nbb3 pe aq s6h be moving to travel 15 m before it decays? The average lifetime, at resq6 b; q(hyed3n z6*/b9gh swapt, is $2.6 \times 10^{-8} \, \text{s}$. v =    c

  What is the momentum of a protowvu70 u) hh qwg2i36iwn traveling at $v =0.85c$? p =    $ \times 10^{-19} \, \text{kg·m/s}$

  At what speed will an object’s relat,z8(hu:c kf0guym0,qvrobf ,ivistic mass be twice its rest mass? v =    c

  A particle of rest mass stxm:ebvoa 5d) /zroe2n l- 34$m_0$ travels at a speed $v =0.20c$. At what speed will its momentum be doubled? v =    c

  (a) A particle travels at3e*+srkdmcr o,)7h 13fkyn aq $v =0.10c$. By what percentage will a calculation of its momentum be wrong if you use the classical formula?    %
(b) Repeat for $v=0.90c$.    %

  What is the percent change in momentum of a pnt w).hk .nv.froton that accelerates
(a) from 0.45c to 0.90c,    %
(b) from 0.90c to 0.98c?   %

  A certain chemical reacti.38d/cbh nhe kon requires $4.82 \times 10^4 \, \text{J}$ of energy input for it to go. What is the increase in mass of the products over the reactants?$\bigtriangleup m$ =    $ \times 10^{-13} \, \text{kg}$

  When a uranium nucleus at rest breaks apart in the pr ohqarw*h g .-j0pvia0e-a- w8ocess known as fission in a nuclear reactor, the resulting fragments have a total kinetic energy of about 200 MeV. How much mass was lostajph* q-.-aoa g0we8hi rw -0v in the process? $\bigtriangleup m$ =    $ \times 10^{-28} \, \text{kg}$

  Calculate the rest energy of an ezub +e((x p4em1:y:yy k*a*h-kd r dnulectron in joules and in $\text{MeV}$ ($1 \, \text{MeV} =1.60 \times 10^{-13} \, \text{J}$).E =    $ \times 10^{-14} \, \text{J} = 0.511 \, \text{MeV}$

  Calculate the rest mass of a protot4i- : th9axumg 44qann in $\text{MeV}/c^2$. $m_0$ =    Mev/$c^2$

  The total annual energy g rn1b ju0o,ap :.sy7aconsumption in the United States is about $10^{19} \, \text{J}$. How much mass would have to be converted to energy to fuel this need?    kg

  How much energy can be obtainey5o n;e+ tdo0td from conversion of 1.0 gram of mass?    $ \times 10^{13} \, \text{J}$How much mass could this energy raise to a height of 0.25 km above the Earth's surface?   $ \times 10^7 \, \text{kg}$

  What is the speed of a particle when its kinetic energy equmtz5 m yj.14jy41dryfqbw). tx h4w1c als its rest energy? v4mw.r41t .5xzm14 yw)j df1 b cqyyjth =    c

  At what speed will an .lridm c7x2l8object's kinetic energy be 25% of its rest energy? v =    c

  (a) How much work is required to accelerate a proton from rest k9fmc2 5mbxt*hncj1: up to a speed of 0.5xn*m2fthbcm:1j k 9c997c? W =    GeV
(b) What would be the momentum of this proton?p =    $ \times 10^{-18} \, \text{kg·m/s}$

  Calculate the kinetic energy anoy mbn yr)qb5.y x/;b0 n9ah9bd momentum of a proton traveling $2.60 \times 10^8 \, \text{m/s}$.
KE =    $ \times 10^{-10} \, \text{J}$
p =    $ \times 10^{-18} \, \text{kg·m/s}$

  What is the momentum of a 750-MeV proton (thfjgo/6d zzg;7at is, its kinetic energy is 750 MeVo;df z6g7jz /g)?    $\times 10^{-19} \, \text{kg·m/s}$

  What is the speed of a proton acceleratedlhbpoy 4uk-fle7 ;0 u/ by a potential difference of 105 MV? v =uy ; oe-7 0hlpl/fkbu4    c

  What is the speed of a;l qsj cs(3,dhn electron whose kinetic energy is 1.00 MeV? v =    c

  What is the speed of an electronwlgzkb pe352-i c0yu ( just before it hits a television screen after being accelerated from rest by the 25,000 V oik bu g250 zecyp(lw3-f the picture tube? v =    c

Two identical particles of rest maedm+ .gl) r pf9:*okscss $m_0$ approach each other at equal and opposite speeds $v$. The collision is completely inelastic and results in a single particle at rest. What is the rest mass of the new particle? How much energy was lost in the collision? How much kinetic energy is lost in this collision?

  Calculate the speed ofvg3ggl j0 :2qe k7k:yb a proton ($m_0 =1.67 \times 10^{-27} \, \text{kg}$) whose kinetic energy is exactly half
(a) its total energy, v =    c
(b) its rest energy.v =    c

  What is the speed an,g2hkhcj vhb35 5ew;z d the momentum of an electron ($m=9.11 \times 10^{-31} \, \text{kg}$) whose kinetic energy equals its rest energy?
v =    c
p =    $ \times 10^{-22} \, \text{kg·m/s}$

  Suppose a spacecraft of mass 27,000 kg is acqp;o-ttu:.31 psigg wcelerated to 0.21c.
(a) How much kinetic energy would it have? KE =    $ \times 10^{19} \, \text{J}$

(b) If you used the classical formula for kinetic energy, by what percentage would you be in error?    %

  Calculate the kinetic energy and mom.d:c cl, tjrmph; 3is 0+2mxtyentum of a proton ($m_0 =1.67 \times 10^{-27} \, \text{kg}$) traveling $7.35 \times 10^7 \, \text{m/s}$. By what percentages would your calculations have been in error if you had used classical formulas?
KE =    $ \text{MeV} \, $ with an error of    %
p =    $ \times 10^{-19} \, \text{kg·m/s}$ with an error of    %

  The americium nucleud- q bzqu i*ps+24uuwk5+pgj.s, $^{241}\text{Am}$, decays to a neptunium nucleus, $^{237}\text{Np}$, by emitting an alpha particle of mass 4.00260 u and kinetic energy 5.5 MeV. Estimate the mass of the neptunium nucleus, ignoring its recoil, given that the americium mass is 241.05682 u. $m_{Np}$ =    u

  An electron ($m_0 =9.11 \times 10^{-31} \, \text{kg}$) is accelerated from rest to speed $v$ by a conservative force. In this process, its potential energy decreases by $6.60 \times 10^{-14} \, \text{J}$. Determine the electron's speed $v$. v =    c

Make a graph of the kinetic energy versus momentum for (a) g fsq9n)sg3 vz ccp(;g5 25shsa particle of nonzero rest mass, and (b) a particle with zero rest mass.gpn3q5 g9;cs h2g)5vsc fss(z

  What magnetic field intensity is needed to ke*fc9t kxim(* rxm. .xhep 998-GeV protons revolving in a circle of radius 1.0 km (at, say, the Fermilab synchrotron)? Use the relativistic mass. The proton' (m* .h9.xfcir m*kxxts rest mass is $0.938 \, \text{GeV}/c^2$ ($1 \, \text{GeV} =10^9 \, \text{eV}$). [Hint: in relativity, it is still true that $\frac{mv^2}{r}=qvB$ in a magnetic field.] B =    T

  A person on a rocket traveling at 0.50c (with-+ nm0zws/gkc respect to the Earth) observes a meteor come from behind and pass her at a speed s ckmgzw/0+-nshe measures as 0.50c. How fast is the meteor moving with respect to the Earth? u =    c

  Two spaceships leave Earth in opposite direc;dwn0sahky 3 1tions, each with a speed of 0.50c with respect0h ns3dway;1 k to Earth.
(a) What is the velocity of spaceship 1 relative to spaceship 2? u =    c
(b) What is the velocity of spaceship 2 relative to spaceship 1?u =    c

  A spaceship leaves Earth traveling at 0.71c. A second spaces9t 0 8chwc3zcnhip leaves the first at a speed of 0.87c with respect to the first. Calculate the speed of the second ship with re c9wzh03c n8tcspect to Earth if it is fired
(a) in the same direction the first spaceship is already moving, u =    c
(b) directly backward toward Earth.u =    c

  An observer on Earth sees an alien vessel approach at a speed of 044q4kt i+hg yuuw8+ fa.60c. The Enterprise comes to the rescue (Fig. Below), overtaking the aliens while moving directly toward Earth at a speed ofuk44 t i4++8gayh fqwu 0.90c relative to Earth. What is the relative speed of one vessel as seen by the other? u =    c

  A spaceship in distress ,dqegl3-c2 lg-l tjo4ohcj ,;(g +rtgsends out two escape pods in opposite directions. One tratojt gegh cgdj (ogl3+,-r; -lql2c4,vels at a speed $v_1 =-0.60c$ in one direction, and the other travels at a speed $v_2 =+0.70c$ in the other direction, as observed from the spaceship. What speed does the first escape pod measure for the second escape pod? u =    c

  Rocket A passes Earth at a speed of 0.75c. At the same time, rocket Bl kgiwf7q -n ppv/ ;brlxp3u91:z (7zb passes Earth moving 0.95c relbplqv;w3z(p p7 :/l-1ugz f9ibrn7kxative to Earth in the same direction. How fast is B moving relative to A when it passes A? u' =    c

  The nearest star to Earth is Proxima Cbsc 8*wa bh8c*l a2c(ientauri, 4.3 light-years away.
(a) At what constant velocity must a spacecraft travel from Earth if it is to reach the star in 4.0 years, as measured by travelers on the spacecraft?    c
(b) How long does the trip take according to Earth observers?$t_{Earth}$ =    yr

  As a rule of thumb, anything travelio d5(2ztr*(. c dlhtp*b i+mykng faster than about 0.1c is called relativistic - i.e., for which the correction using special relativitycr(ky(mdt.iodt 5 l+2z*p*hb is a significant effect. Determine the speed of an electron in a hydrogen atom ($v \approx 2.2 \times 10^6 \, \text{m/s}$) and state if it is relativistic. (Treat the electron as though it were in a circular orbit around the proton.) ----待选择----relativistic not relativistic 

  (a) What is the speedz c9soa6 g6r4w $v$ of an electron whose kinetic energy is 14,000 times its rest energy? You can state the difference $c - v$. Such speeds are reached in the Stanford Linear Accelerator, SLAC.    m/s less than c
(b) If the electrons travel in the lab through a tube 3.0 km long (as at SLAC), how long is this tube in the electrons' reference frame? [Hint: use the binomial expansion.]L =    cm

  How many grams of matter would have to be totally destrni3*ko+pp i)e(az 16d iqejp0oyed to run a 100-W lightbulb for 1 year? (ea3qiz0jik1d+e*i6 )p opp n $m_0$ =    $ \times 10^{-8} \, \text{kg}$

  What minimum amount of electromi3umk c;/jp7: m, anojgveu9 8agnetic energy is needed to produce an electron and a positron together? A positron is a particle with the same rest mass as an electron, but has the opposite charge. (Note that electric cha:u,vk38/gjm oeiju c;npm79a rge is conserved in this process.) E =    MeV

  An electron ($m=9.11 \times 10^{-31} \, \text{kg}$) enters a uniform magnetic field $B=1.8 \, \text{T}$, and moves perpendicular to the field lines with a speed $v=2.5 \times 10^7 \, \text{m/s}$. What is the radius of curvature of its path? r =    mm

  A negative muon traveling v sp/jnfu0cs 64g )a0dat 33% the speed of light collides head on with a positive muon traveling at 50% p dns0c0v 4 as6/fju)gthe speed of light. The two muons (each of rest mass $m_\mu = 105.7 \, \text{MeV}/c^2$) annihilate, and produce how much electromagnetic energy?E =    MeV

  A free neutron can decay into a proton, an electron, and a neutrino. Assume8c 4b+c8cr9ca kqylwxlpv7 / / the neutrino's rest mass is zero, and the other masses can be found in the Table inside the fr7acx8l4 v98kbqr+cl ycp wc//ont cover. Determine the total kinetic energy shared among the three particles when a neutron decays at rest. KE =    MeV

  The Sun radiates energyx+. pg ,q k5ctzkme .as2vv8m3 at a rate of about $4 \times 10^{26} \, \text{W}$.
(a) At what rate is the Sun's mass decreasing?$\frac{\Delta m}{\Delta t}$ =    $ \times 10^9 \, \text{kg/s}$
(b) How long does it take for the Sun to lose a mass equal to that of Earth?$\Delta t$ =    $ \times 10^{15} \, \text{s}$
(c) Estimate how long the Sun could last if it radiated constantly at this rate.$\Delta t$ =    $ \times 10^9 \, \text{yr}$

  An unknown particle is measured to*l kc6ik ibw6ht-x;g) have a negative charge and a speed of $2.24 \times 10^8 \, \text{m/s}$. Its momentum is determined to be $1.07 \times 10^{-22} \, \text{kg·m/s}$. Identify the particle by finding its rest mass.
 ----待选择----electronpositron 

  How much energy would be required to break a helium nucleus into its constituenp /xb2ae8wi9w ts, two protons and two neutrons? The rest 28 /wpxwiba9 emasses of a proton (including an electron), a neutron, and helium are, respectively, 1.00783 u, 1.00867 u, and 4.00260 u. (This energy difference is called the total binding energy of the $^4\text{He}$ nucleus.) KE =    MeV

  What is the percentage increaseey(*n a)j d,uq in the (relativistic) mass of a car traveling 110 km/h as compared to at rest? [Hint: jeda(y*n u,q)use the binomial expansion.]$\frac{\left(m-m_0\right)}{m_0}$ =    $\times 10^{-11}\%$

  Two protons, each having a sb;, (xlywh.oag1i /g ppeed of 0.935c in the laboratory, are moving toward each hw(y /xgpoi;.a1gl ,b other. Determine
(a) the momentum of each proton in the laboratory, u =    $ \times 10^{-18} \, \text{kg·m/s}$
(b) the total momentum of the two protons in the laboratory,   
(c) the momentum of one proton as seen by the other proton.p =    $ \times 10^{-18} \, \text{kg·m/s}$

Show analytically that a particl7jpel c:) rh8gwctt74e with momentum $p$ and energy $E$ has a speed given by $v = \frac{pc^2}{E}$.

  The fictional starship Enterprise obtains its power by /1s+ed-d0xy2dy naz k combining matter and antimatter, achieving complete conversion of mass into energy. If the mass of the Enterpri zdx2s+yd/1y 0-nek dase is approximately $5 \times 10^9 \, \text{kg}$, how much mass must be converted into kinetic energy to accelerate it from rest to one-tenth the speed of light?    $\times 10^7 \, \text{kg}$

  An electron is accelerated so that its kinetic ene4ud9; k9p 9zbdnbxub* rgy is greater than its rest mas4;d9 9 nz 9uxbukbdp*bs $m_0c^2$ by a factor of
(a) 5.00, v =    c
(b) 999. What is the speed of the electron in each case?v =(1 -    $ \times 10^{-7}c$)

  A farm boy studying physics believes that he cag3n:sxic+6 v zn fit a 15.0-m-long pole into a 12.0-m-long barn if he runs fast enough (carrying the pole). Can he d+xi:6vsgc n z3o it? Explain in detail. How does this fit with the idea that when he is running the barn looks even shorter to him than 12.0 m? ----待选择----possiblenot possible 

  When two moles of hydrogen and one mole of oxygen react to form two moles of )jq 8fbch,j+c water, the energy released is 484 kJ. How much does the mass of the elements decrease in this reactioq c8jf,hc+b)jn?
$\Delta m$ =    $\times 10^{-12} \, \text{kg}$
What % of the total original mass of the system does this mass change represent?    $ \times 10^{-8}\%$

  In a nuclear reaction two identical particles are created, travelingv iv)g r)hkui* 5-4tgk in opposite directions. If the speed of each particle is 0.75c, relativikr)h4-gut k)5vg i *ve to the laboratory frame of reference, what is one particle's speed relative to the other particle? u =    c

  An astronaut on a spaceship traveling at 0.75c relative to Earth meas+n;ovac c u(9uures his ship to be 25 m long. On the shipvuau cn;(oc+ 9, he eats his lunch in 23 min.
(a) What length is the spaceship according to observers on Earth? L =    m
(b) How long does the astronaut's lunch take to eat according to observers on Earth? $\Delta t$ =    min

You are traveling in a spaceship at a speed of 0.85c away from Earth. You send a)vd( r9vq7) g- wsfjoe laser beam toward the Earth traveling at velocity c relative t7(-fs dg9vwv qej) ro)o you. What do observers on the Earth measure for the speed of the laser beam?

  A spaceship and its occupants have a total mass l510m3fg8fk0ll4 yt9amj qx bof 150,000 kg. The occupants would like to travel to a star that is 25 light-years away at a speed of 0.60lxlm5q10y4mfjg9f0a3 tbk8l c. To accelerate, the engine of the spaceship changes mass directly to energy. How much mass will be converted to energy to accelerate the spaceship to this speed?    kg
Assume the acceleration is rapid, so the speed for the entire trip can be taken to be 0.60c, and ignore decrease in total mass for the calculation. How long will the trip take according to the astronauts on board?$\Delta t_0$ =   y

  Suppose a 12,500-kg spaces2y;t nge(c 2f0u9 i2rbjciup 4hip left Earth at a speed of 0.99c. What is the spaceship's kinetic energy? Compare with the total U.S. annual energy con2jiecyu nr22 c9g;tui4b (0fpsumption (about $10^{19} \, \text{J}$). KE =    $ \times 10^{20} \, \text{J}$

  A 42,000-kg spaceship is to travel to the vicinity of a star 6x h;ba1 x g2cej4t2t.o u+z;kv.0 light-years from Earth. Passengers on the ship want the (one-way) trip to take no more than 1.0 year. How much work must be done on the spaceship to bring it to the speed necessa 41t.x;eug2baohc2kv+x z tj;ry for this trip? u =    c

  A 1.68-kg mass oscillates on the end of a spring j8ah qncuxay3q452a. e:h ey-( ia-n3ptfna+ whose spring stiffness constant is p8h afqne- i5j4nh(u cy:+y2ta q a3e3anx. a-$k=48.7 \, \text{N/m}$. If this system is in a spaceship moving past Earth at 0.900c, what is its period of oscillation according to
(a) observers on the ship, T =    s
(b) observers on Earth? $T_{earth}$ =    s

A pi meson of rest maszug5 9tn8n(i.h. xe qos $m_\pi$ decays at rest into a muon (rest mass $m_\mu$) and a neutrino of negligible or zero rest mass. Show that the kinetic energy of the muon is $KE_\mu = \frac{(m_\pi - m_\mu)^2 c^2}{2m_\pi}$.