You are in a windowless car in an l /*a**pw*:hrv) z 9disj wfbjexceptionally smooth train moving at constant velocity. Is there any physical experiment you can do in the train car to determine whether you are moving h)i*ajl/rw*fpds z v*j9b:w*? Explain. ----待选择----yesno 

You might have had the2mt. mx( (eksb experience 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 t( bksxm.e2m( are rolling backward. What does this say about absolute and relative motion?

A worker stands on top of a moving rainnc b0.v1ydwv xs:d.(d v 8wb7lroad car, and throws a heavy ball straight up (from his point of view). Ignoring air resistance, will the ball land on the car or behind bdx7.d v:wsv wcb8nny0. 1d v(it?

Does the Earth really go around the Sun zswa)kw:*f8 sr ,rfpk74 uq*.gar(gy? Or is it also valid to say that the Sun goes around the Earth? Discuss in view of the first principle of relativigrwf(sayk*4 8r a.)z p7g:,rw fs* qkuty (that there is no best reference frame). Explain.

If you were on a spaceship traveling at is6i* akt8fmpp*ie/ / 0.5c away from a star, at what speed would the starlightp6ii/pmk **s8/efia t pass you?

The time dilation effect is sometimes expressed as “moving clz3.hwe* bdjc;n m. lx(ocks run slowly.” Actually, this effezcn; (m3*hd x.. bwjlect has nothing to do with motion affecting the functioning of clocks. What then does it deal with?

Does time dilation mean that time actual-:jg x;7gkfc5 gi0fk lly passes more slowly in moving reference frames or that ig7cx 5kl0jf;fgik :g- t only seems to pass more slowly?

A young-looking woman astronaut has just ar2, 2gb xslsj d,tgq(*krived home from a long trip. She rushes up to an old gray-haired man and in the ensuing conversation refers to him as her son. How might t,dqs(g t,k*2sgl2xbjhis be possible?

If you were traveling away from Earth at speed 0.5c,w+-8oav efuu ( would you notice a change in your heartbeat? Would your mass, height, or waistline change? What would observers on Earth using telesco+uu awv-8ef (opes say about you?

Do time dilation and length contraction occur at ordinary sp(2c qdoobs;fi4sj 1,veeds, say $90 \, \text{km/h}$?

Suppose the speed of light were infinite. What would happen to the relati:d3y l-flrz:t f2ww0 u m-l1pavistic predictions of le :-ar dl2 3y1ztw:pfwul0-lm fngth contraction and time dilation?

Discuss how our everyday lives would be different if the speis y+i)rui1 z:ed of light were only rs1)ui+yizi: $25 \, \text{m/s}$.

Explain how the length contraction and tim - gr8n kzr7zhr*6jak+e dilation formulas might be used to indicate that r-h6z7a8gk+j* zkn rr c is the limiting speed in the universe.

The drawing at the start ofj*d 3wta 39pqr vyb9tv8hk0p - this Chapter shows the street as seen by Mr Tompkins, for whom the speed of light is8q39* pd hjwka t9v3vbyp0r t- $c=20 \, \text{mi/h}$. What does Mr Tompkins look like to the people standing on the street? Explain.

  An electron is limited to travel at speeds les g ku74+z+tmgjs than c. Does this put an upper limit on the momentum of an electron? If so, what is this upper limit? If not, explaintm+u + 7gkzjg4. ----待选择----yesno 

  Can a particle of nonzero rest mass attain the speed of light8e4irafs qq8(dp * qw7bt.e/t? ----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 tlydpi ,pguy.e /-4zs -hat a spring has more mass when compressed than wh / 4il-sezpdp.-yugy,en relaxed? ----待选择----yesno 

It is not correct to say that "matter can ne7x8-ew oyjv9xjb k.dmp)zg5 , ither be created nor destroyed." What must we say insteawx m ,o.-k58vxg 7b) jedpyzj9d?

  Is our intuitive notion that velocities simply add, asw)f).c 3hle0kjaif * y7m5xtk we did in Section 3–8, completely wrong?.e7) hky3wcfkaf* xj )m0 5lit ----待选择----yesno 

  A spaceship passes you3nemm6k q //tz at a speed of 0.750c. You measure its length to be 28.2 m. How long would it bek// e6t3qzmnm when at rest? $L_0$ =    m

  A certain type of elementary particle travels at a speeqre 4v3ytir jv7cvh 87 ;k93-iv/jijxd 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 the6d k h(sm9zm4a nf)5oe factor $\beta = \frac{1}{\sqrt{1 - v^2/c^2}}$ 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 light-years from Earth at a spee wi1h:hhbd.c/ 29 szu4c 6xqgod of $2.50 \times 10^8 \, \text{m/s}$, what would you measure this distance to be? L =    ly

  What is the speed of az2 kts/d n7ywd 9,py9a pion if its average lifetime is measured to be $4.10 \times 10^{-8} \, \text{s}$? At rest, its average lifetime is $2.60 \times 10^{-8} \, \text{s}$. v =    c

  In an Earth reference frame, a star is 82 light-years away. How fastfvx.6-v5g8 ir8uej4bt 0w efq would you have to travel so that to you the distance would be only 35 lig.4 5-x6ftw8fb rvi0jq8ueve ght-years? v =    c

  Suppose you decide to travel to a star 85 light-y v fnl( t5/yt5)q r75zvddep*v1tq.zvears away at a speed that tells you the distance is only 25 light-years. How many years would it take you to7v1q zq( l)tzv 55 5t/dvpdftnvr*e y. 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 Eart84:+wwwmbc thq qp /k8h 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 starship Enterprise n )+bvfcb8 wr0wenk1.had just returned from a 5-y1k .b)v nbne0+fcw8wrear voyage while traveling at 0.84c.
(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. Hgq)l) wj:jb5+s-bkx low long would it take a spacecraft traveling 0.960c to reach thalx) gbb:-j )l 5wk+qsjt 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 her "Ferrari" spacecraft at a speed of 0.660c. It is e3 qk:nhiy*z4+oshn8 measured in your frame to be 4.80 m long and 1.2 4*ezks3o n +qihhy8n:5 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 pv-un kf5ft: ;xion be moving to travel 15 m before it decays? The average lifetime, ;f-n ftxku5v:at rest, is $2.6 \times 10^{-8} \, \text{s}$. v =    c

  What is the momentum of a prqnyki 8 80nxx+oton traveling at $v =0.85c$? p =    $ \times 10^{-19} \, \text{kg·m/s}$

  At what speed will an object’s relativistic mass be twice it.w6 dq+ yj.jvg7)yzqks rest mass? v =    c

  A particle of rest ma g ;3(+mmep1rq oxsr3ess $m_0$ travels at a speed $v =0.20c$. At what speed will its momentum be doubled? v =    c

  (a) A particle travew :(p+hu pwq;als at $v =0.10c$. 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 chan;vmf ++(yiunlr97y jrge in momentum of a proton that accelerates
(a) from 0.45c to 0.90c,    %
(b) from 0.90c to 0.98c?   %

  A certain chemical reaction reqi0fdi17r0 7f2 d cqd hnn+ohxbc0y y4,uires $4.82 \times 10^4 \, \text{J}$ 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 process known a hcu h-ch 7.k)li 3hdfz. 9x4p9vrm)lys fission in a nuclear reactor, the resulting fragments have a total kinetic energy ozcx9u )9k.dh fhy4.)-cihl l7hm3pv rf about 200 MeV. How much mass was lost in the process? $\bigtriangleup m$ =    $ \times 10^{-28} \, \text{kg}$

  Calculate the rest energy of an electr kzafn1+md6rh: w017on w xn,yon 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 o 6w ,,t)xcsv4yki xit+f a proton in $\text{MeV}/c^2$. $m_0$ =    Mev/$c^2$

  The total annual energy consu suvq y0uj-jmpa*v.28l;trnc,v kr0 +u pcn8)mption 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 obtained fro9 e6 ih.o;kn;qjyzx5tm 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 4hm9n su6b9ybuj)j q5,n 06sfcm ztz 2when its kinetic energy equals its rest energy? v9cm,96s6jtbsqh5n j )z 2zby 4u0mn uf =    c

  At what speed will an object'sdp5(g5 bbupx 05dsq zdk:un5 0 kinetic energy be 25% of its rest energy? v =    c

  (a) How much work is required to accelerate a proton from rest up toqtp;.: k8m*e-jf aqru a speed of 0.997f mkqr :atpeq *uj.-;8c? W =    GeV
(b) What would be the momentum of this proton?p =    $ \times 10^{-18} \, \text{kg·m/s}$

  Calculate the kinetic energy and momentum of a proton trans/mhevw 0k2:x v4* ee.(ajnyveling $2.60 \times 10^8 \, \text{m/s}$.
KE =    $ \times 10^{-10} \, \text{J}$
p =    $ \times 10^{-18} \, \text{kg·m/s}$

  What is the momentum of a 750-MeV proton (that is, its kinetic energy is 750 MeVme( a 5qltvx6))? a tvmql) e6(x5   $\times 10^{-19} \, \text{kg·m/s}$

  What is the speed of a proton accelerated by a p 8:;ne adkbhxio t)5s6otential difference of 105 MV? vhbkn;8dao:56 sexti ) =    c

  What is the speed of an elt:bicp+o:)+f1y 0 dixzc2qbnectron whose kinetic energy is 1.00 MeV? v =    c

  What is the speed of an electron just before it ,:fot yewsss:r / c96ghits a television screen after being accelerc/:6f og esy9s,ts:wrated from rest by the 25,000 V of the picture tube? v =    c

Two identical particles of rest masqz*yr4;hp-0kx ; expt s $m_0$ 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 of a+d f3q 9y th ey(/i2rb 1zy4jtooxm;.n 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 and the momentum of ;iw)7n.8 w 3 ok yfja6:gcxjy*v;hdhxan 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 accelerated to 0.2.al7j4-xobsl w -ltyd p,v+. g6 p8wnc1c.
(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 kineti gnsk,r-u955tmr pe z/c energy and momentum 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 nucleus(yp1mq awzjqw.c* z 69, $^{241}\text{Am}$, 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 ki(om0y y2vt.fm9e 8t amnetic energy versus momentum for (a) a particle of nonzero rest masoe mtt2 v9.f8( 0mmayys, and (b) a particle with zero rest mass.

  What magnetic field intensity is needed to keep 998-GeV protons revol)m 9hrdh6: zgaving in a cir9)6ah zr: ghmdcle of radius 1.0 km (at, say, the Fermilab synchrotron)? Use the relativistic mass. The proton's 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 rockethxij1h 0h(xh( traveling at 0.50c (with respect to the Earth) observes a meteor come from behind and pass her at a speed she measures as 0.50c. How fast is the meteor moving with 1x0hxi(hjh(h respect to the Earth? u =    c

  Two spaceships leave Ea 4b54q31iu hn0*sxcxqp 8 pfsjrth in opposite directions, each with a speed of 0.50c with respect tj1nqqixh 40p8 s43ufs5pbx *co 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 g 36gi*e ty;yltraveling at 0.71c. A second spaceship leaves the first at a speed of 0g3geyly 6t;i*.87c with respect to the first. Calculate the speed of the second ship with respect 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 anmwflwp4/4o4r alien vessel approach at a speed of 0.60c. The Enterprise comes to the rescue (Fig. Below), overtaking the aliens while moving directly toward Earth at a speed of 0.90c relative to Earth. What is r4lwpf44mow/ the relative speed of one vessel as seen by the other? u =    c

  A spaceship in distress sends out two escape pods in opposite directio4i.qw i,5lgorjs h r; 2t 62dbxfs5-zons. One travels at a 5q t.6-bizf;r4l2dxr5ho jgs, 2 swiospeed $v_1 =-0.60c$ 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 B passes6a)a8 7tra msn qj78kl Earth movins6ja k7atma)rl7q 8 8ng 0.95c relative 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 Proxitokw4 lr 52 8i+m7rl0ge8tzdc1 inm, tma Centauri, 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 traveling faster than about 0.1c is called rel+ mbi(bc7vdapzd 1y05 ativistic v bb7c5a+m 1d pz0yi(d- i.e., for which the correction using special relativity 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 speed mgxe qh172ieq7c1 5zt$v$ 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 destroyed to run a 1a4v. 9ayjq1; ;de4zwssrv8p y 00-W lightbulv dvep 9y4a81sws;.zr ;a yqj4b for 1 year? $m_0$ =    $ \times 10^{-8} \, \text{kg}$

  What minimum amount of electromagnetic energy is needed to produce an elecrurla,mzyk )k*f23-x tron and a positron together? A polau-*,3mkzf)kx rr2 y sitron is a particle with the same rest mass as an electron, but has the opposite charge. (Note that electric charge 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 at 33% the speed of light coll/: xsl lu6 b e;1g1fvui;jww/aides head on with a positive muon traveling at 50% the speed of light. The two muons (each ofj ;vw1l;l :/ex i6a1u/fbuwgs 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 protonrtd ya/*c ho1)c,qd:e, an electron, and a neutrino. Assume the neutrino's rest mass is zero, and the other masses can be found in the Table inside the front cover. Determine the total kinetic energy shared among the three particles when a neutron decayyoc1/:h )dtaeqd, c *rs at rest. KE =    MeV

  The Sun radiates energy at a rate of ab +q-mnjbx8c 4ujrea .2out $4 \times 10^{26} \, \text{W}$.
(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 have a eb+nw3wra ,/5+gdvnynegative 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 requxw(2mp hyf 50t*zj/)kzhs zn 5ired to break a helium nucleus into its constituents, two protons and two neutrons? The rest masses of a proton (including an electron), a nsk0 5xpfnzh/ zhj5y2)*( mzwteutron, 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 increase in the (relativistic) mass of a car tw/t(hx*h i g6xcl/h3v raveling 110 km/h as compared to at rest? [Hint: use the binomial expansio*xivl3hx hgt/c/w(h6 n.]$\frac{\left(m-m_0\right)}{m_0}$ =    $\times 10^{-11}\%$

  Two protons, each having a speed of 0.935c in the laboratory, are movin,*lwp82oczlzn m a( e3g toward eac l3m2wa zp o(zn,*ce8lh 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 particle with moment;grw.l,9u.m yt cao 1gum $p$ and energy $E$ has a speed given by $v = \frac{pc^2}{E}$.

  The fictional starship Enterpxbhxq8-t21kj :cx2fi rise obtains its power by combining matter and antimatter, achieving complete conversion of mass into energy. If the mass of the Enterprise is approximatelyxx-xc1qb j:8fih2 2kt $5 \times 10^9 \, \text{kg}$, 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 energy is greater than its*qi( q 4b (3-b3;lkmvnrfwf vq rest m v3-nqiwl *rbkf 3bv(f;4m q(qass $m_0c^2$ 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 o1qhy (1.zfn acan fit a 15.0-m-long pole into a 12.0-m-long barn izy .h n1faoq1(f he runs fast enough (carrying the pole). Can he do 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 twyi v 8d,fo k6r+yet:+ c*h3utz2ja6ovo moles of water,jhavoy vy2+6d f*6,:+ tc ozk38u trie the energy released is 484 kJ. How much does the mass of the elements decrease in this reaction?
$\Delta m$ =    $\times 10^{-12} \, \text{kg}$
What % of the total original mass of the system does this mass change represent?    $ \times 10^{-8}\%$

  In a nuclear reaction two identical particles artup3sas td6qh vxj(9,+cg/dfe0 6 (d re created, traveling in opposite directions. If the speed of each particle is 0.75c, relative to the laboratory frame of reference, what is o /asf+c,((v30qtpdrx66suegd h9 d tjne particle's speed relative to the other particle? u =    c

  An astronaut on a spaceship traveling at 0.75c relative to Earth measm;ja7kx/7b s uures his ship to be 25 m long. On the ship, he eat7;auj/m sxb k7s 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 space/5mliet rtn :8ship at a speed of 0.85c away from Earth. You send a laser br/m l it5etn:8eam toward the Earth traveling at velocity c relative to you. What do observers on the Earth measure for the speed of the laser beam?

  A spaceship and its occupants have a total mass of 150,000 3xegm/fbf *s3kg. The occupants would like to travel to a star that is 25 light-years away at a speesb*fgf mx/3 3ed of 0.60c. 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 spaceship left Earth at a speed of 0.99c. What is the spacesdluwy/.up8;ix5:7r * sa gupzhip's kinetic energy? Compare with the total U.S. annual ene ua8;supzul7rpx:y/5diw *g .rgy consumption (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 6.0 light- 9pxrl:-,,.uu fcew lryears 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 .p,wc9lfx - :reuu,rlit to the speed necessary for this trip? u =    c

  A 1.68-kg mass oscillates on the end of a spring whose spr nnjkfd;nwhsdsz58a (1d 66x:fnv/5 iing stiffness constant (d5fn: /6ih vnd 8sjsxn5df1 kw;z6na is $k=48.7 \, \text{N/m}$. 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 masjfj4 2e0rdq8*;ldd7guftg, n s $m_\pi$ 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 $KE_\mu = \frac{(m_\pi - m_\mu)^2 c^2}{2m_\pi}$.