Which of Newton's laws best explains why motorists should buckle-up?l *p2 fuv laz:av e3nq5 3uji:w6pa7s.

  When you sit on a chair, the resulta2kjq w6b,0 q/0trwk53 3gad funl o5xint force on you is

  In the absence of an external force, a moving obtu2 o7qqgnv j b5:1:feject will

  When the rocket engines on the starship NO-PAIN-NO-GAIN ce1. :l. o(leflclwn3are suddenly turned off, while traveling in empty s..lc loceel1 :(w3nfl pace, the starship will

  A rocket moves through empty space in a straight line with cons(9 2rxocytav0b9j ck 9e.dh l8tant speed. It is . ex (h9 ly 92ov9jcd08ckrbatfar from the gravitational effect of any star or planet. Under these conditions, the force that must be applied to the rocket in order to sustain its motion is

  You are standing in a moving b.wjo 1-vqmd -;;jhvna+l-q5moraac ra(5t ,kus, facing forward, and you suddenly fall forward. You can imply from this that the b, qm;oa vm;jv5da +k (.-c5-atorqh- w1ljra nus's

  You are standing in a moving busd0btef9wgdppn8b ht 82b07 /r, facing forward, and you suddenly fall forward as the bus comes to an im tbn e78 p0d0b2pf/wb 89dgtrhmediate stop. What force caused you to fall forward?

  A constant net force acts on an object. Desc2zof+gv :*so6vhgf v,8kzsh ; ribe the motion of the object.

  The acceleration of an objec /:.zjs+)saasm c, jont is inversely proportional to

  A net force F accelerates a mass m with an acceleration a. If the s e,k,c8gqsuu+1*0 gkmin dk4rame net force ismkkku* d, esngqiug804,1 cr + applied to mass 2m, then the acceleration will be

  A net force F acts on a mass m and produces an accelera08 gik unn l(xot9*/khtion a. What acceleration resu/hkoug*lt ( n9ix8k 0nlts if a net force 2F acts on mass 4m?

  If you blow up a balloon, and then relfn 2dt4n 1;1mt f-nvwaease it, the balloon will fly away. This is an illustration mw1tdn-1n t ;4vf f2anof

  Two cars collide head-on. At every moment duri*c0d ,l /akhorng the collision, the magnitude of the force the first car exerts on the second is exactly equal to the magnitude of the force the second car exerts on the first. Thisor kd,/*a0lc h is an example of

  If you exert a force F on an object, 4(elv43+ioxq 5jkp w inufu1+ the force which the object exerts on you willuk(3vu514wn jx4 ifelq++pi o

  Action-reaction forcenp8 x-0qxe4e yfchi4: s

  Action-reaction forces syfivioaq+423l( . .dbbna* dare

  A 20-ton truck collides with a 1500-lb car and causes a lot of o73x.s2qc itk8htb);bod ( hj9 ife8sdamage to the car. Since a lot of damage is done on the ca8hqsi;).bihj 9 3 o(d8tsxot 2ce7fbkr

  An object of mass m sits on a flat table. The Earth pulls on this objelqbu:( godtr;p/a ,9 kct with force mg, wh 9:dpbot,/au(g kl qr;ich we will call the action force. What is the reaction force?

  A child's toy is suspended from the ceiliccta ka0d); b-ng by means of a string. The Earth pullabd)-;cct k0 as downward on the toy with its weight force of 8.0 N. If this is the "action force," what is the "reaction force"?

  Your bat hits the ball pitched to you with a 1500-N instant06(,tp jtlvoo aneous force. The bat(06 oj l,voptll hits the bat with an instantaneous force, whose magnitude is

State Newton's three fp 27grh;s w11e y.b qu9bzv1tpmno.(laws.

  Mass and weight

  The acceleration due to gnmkbqk5/ s+c 9ravity is lower on the Moon than on Earth. Which of the following is q s+nmk/5b ck9true about the mass and weight of an astronaut on the Moon's surface, compared to Earth?

  An example of a force which acg*gm/o , rhr, 7bd 6 rdrd18g+l6fotjnts at a distance is

  Who has a greater weight to mass ratio, a person weighij3akpy rl)0h -ng 400 N or a person weighing 600 N? 3yl)r0 hkjp-a

  A stone is thrown straight up. At the top of its pztc5fl,th 6+f ath, the net force acting on it is6hfzfl5c t+t,

  A 20-N weight and a 5.0-N weight are dropped simultanepc/8m+p 6 4i r (w*rfyq7 .mcmlocd:sqously from the same height. Ignore air resistance. Compare their a r6 c4/.lqp87 wmyoqsfc+dm:pmr(c*iccelerations.

  A brick and a feather fall t v 0wnl,imp,f*o the earth at their respective terminal velocities. Which object experiences f*lw, ipm0nv, the greater force of air friction?

  An object of mass m is hanginglhsm*e 4g :z yn20c+ec by a string from the ceiling of an elevator. The elevator is moving nhc4cs* 0lzge:my+e2 up at constant speed. What is the tension in the string?

  An object of mass m is hanging byv utjja8hssg( j/ gh)j.m6n( . a string from the ceiling of an elevator. The elevator is moving upwarsjmjh v aj/((s86h.ug n.gtj)d, but slowing down. What is the tension in the string?

  The force that keeps you from sliding on an icy sidewalk ia3;p ncfh pp,(xd(;o ws

  It's more difficult to start moving a heavy carton from rest than itkhtbo7 l7(ron/ma0w 66e kk z/ is to keep pushing ie6kz/ khm n oatw7b 6(/k7orl0t with constant velocity, because

  A horizontal force accelerates a box from rest aj0 ;)zm dt**zsjlrl1w 1b9zeeeb 5.lrcross a horizontal surface (friction is present) at a constant rate. The experiment is repeated, and all conditions remain the same with the exception that the horizontal force is doubled. What hap r.5 jmw)zstbleb0de1*l;rj 1*z9zle pens to the box's acceleration?

  A packing crate slides down an inclined ramp at co-p;wwxs01d qknstant velocity. Thus we can deduce thad;p0w- sxqkw1 t

  A block of mass M slides down a frictionless plane inclined at w:- imtozs s:s1cwt 51an angle q with the horizontal. The normal reac1s:-z 1csmt ts:o5wwi tion force exerted by the plane on the block is

  A block of mass M slides down a frictionless pfzvqk4 2qni6 (tbz w6i*v,ix)lane inclined at an angle q with the horizontal. The normal reaction force exerted by the plan nzvi(wzbik )qi f62v,*4 qxt6e on the block is directed

  A block of mass M slides down a frictionless plane inclined at an anglmtg- :u :tn*qlo5o+wje q with the horizontal. The gravitational fo*uqn5owtl: g+mo-tj: rce is directed

  Two toy cars (16 kg and 2.0 kg) are released simultaneously . *xnemq .9dk lq1ikc/zphhz0) d*4cuon an inclined plane that makes an angle of 30e with the horizonz)9/ qh*1* p4kczdmecu . qnl.ki x0hdtal. Make a statement which best describes their acceleration after being released.

  An object sits on a frictionlesd ),texxsy8( tokj*s; s surface. A 16-N force is applied to the object, and it actxkj,x*s dos;) t8y( ecelerates at $2.0 \; m/s^2$. What is the mass of the object?

  A sports car of mass 1000 kg can accelerate from rest to 27 m/s in 7.0 s. Wh (-zv;rj1ddbue5h7 enat is the average forward force on theu- (ee7;1dvjr5z ndbh car?

  Starting from rest, a 4.0-kg body reaches a speeb;,tcpm *2avi8gx - f )tjfv1d wi-9hfd of 8.0 m/s in 2.0 s. What is the net forcet mj ;fpv )8,f1xigc*i-t-d9 fhv bwa2 acting on the body?

  An antitank weapon fires a 3.00-kg rocket which acquire98k mbw fq.xcx ;*uq0g-aq5lxs a speed of 50.0 m/s after travelinxmq.b5lkfcw *q; -0q89xguaxg
90.0 cm down a launching tube. Assuming the rocket was accelerated uniformly, what is the average force acted on it?

  If you push a 4.0-kg mass with the same force that you push anbbt423s,--mb+ nph9nzv yp b 10-kg mass from resth2m3 ytn pbv -bnbzbp9+-s,4 n,

  What is the mass of a person who weighs 110 l djgbf+o)gu0* vm 4g3rsd fek /46r,clb?

  What is the mass of an object o )6wkkg*v5ehm2* fj5q vzzl( that weighs 250 N on the surface of the Earth where the acceleration due to gravity is kqwkl*vh(m5gfz* j5oz 2e)6 v$9.80 \; m/s^2$?

  An object has a mass of 60 kg on the Earth. What is thbq)b p(9f:wjj e mass of the object on the surface of the Moon where the acceleration due to gravity is only 1/6 )qf9 (w:jpbbjof that on the Earth?

  Object A weighs 40 N on Earth, and object B wv,azti).o s0*yxv9a q eighs 40 N on the Moon. The Moon's gravity is one sixth of Earthyvsx.a*)9 za ,qovi0t 's. Compare the masses of the objects.

  Sue and Sean are having a tug-of-war by pulling on opposite ends of 0 2p:/bstbav;up+ n fky.ktz 0a 5.0-kg ropt;p0 p. :vb tanu0f+sb/2ky zke. Sue pulls with a 15-N force. What is Sean's force if the rope accelerates toward Sue at $2.0 \; m/s^2$?

  A stack of books rests oz 0*ccf qq8tc6y-p lu2n a level frictionless surface. A force F acts on the stack, and it accel 0clpq2ut8f q6 -zccy*erates at $3.0 \; m/s^2$. A 1.0 kg book is then added to the stack. The same force is applied, and now the stack accelerates at $2.0 \; m/s^2$. What was the mass of the original stack?

  A person of weight 480 N stands on a scale in an elevator. What will thtxcmjj 91do+p6fvb62 e scale be reading when the elevator is accjjvfm p+x b2cd1ot669 elerating downward at $4.00 \; m/s^2$?

  A person on a scale rides in an elevator. If the mass of the person is :ws 7lli7gr6f60.0 kg and the7 7f rllw6gsi: elevator accelerates downward with an acceleration of $4.90 \; m/s^2$, what is the reading on the scale?

  A person on a scale rides in an elevator. If the mass of the person ib5e0yb );kwxiy 1ix w,s 60.0 kg and wyixex1bw,; k5 )i0yb the elevator accelerates upward with an acceleration of $4.90 \; m/s^2$, what is the reading on the scale?

  Two horizontal forces act on a 5.0-kg mass. One force has a mal j(6kdp w2,l7.ggs nsfoh36vgnitude of 8.0 N and is directed due north. The second force toward the east has a magnitude of 6.0 N. What is t27 63skj,lldp v(fgos. gwn 6hhe acceleration of the mass?

  An object of mass 6000 kg rests on the flatbed of a truck. 7t1:zyd kcw ash3 rct:h:oj*. It is held in place by metal brackets that can exert a maximum horizontal force of 9000 N. When the tru7h::. cdatkso3:c1 z*h rwytj ck is traveling 15 m/s, what is the minimum stopping distance if the load is not to slide forward into the cab?

  An object of mass 6000 kg restz( s6l9pl8(nwcbsdb f e2*b2 ms on the flatbed of a truck. It is held in place by metal brackets that can exert a maximum horizontal force of 9000 N. When the truck is traveling 15 m/s, what is the minimum stopping timbnz f9se6*p2b (lcw sm2l(b 8de if the load is not to slide forward into the cab?

  In the Atwood machine shown in Fig. 4-1, if M = 0.laj:4wu 4x0war**ru6 rdo b, m60 kg and m = 0.40 kg, what is the magnitude of the acceleration of tw ru,4:rl*064 a dm oraxubj*whe system? (Ignore friction and the mass of the pulley.)

  In the Atwood machine shown in Fig. 4-1, if M = 09 cdc gwta+elco4nri:cf p5 zp;46p4:.60 kg and m = 0.40 kg, what is the tensip+cta5n :l4c o cg4c6edi ;f:rp9w zp4on in the string? (Ignore friction and the mass of the pulley.)

  A student pulls a box o 4hxjjf6zg)k)f books on a smooth horizontal floor with a force of 100 N in a direhj)xf jzg4)k 6ction of $37^{\circ}$ above the horizontal. If the mass of the box and the books is 40.0 kg, what is the acceleration of the box?

  A student pulls a box of books on a smooth hohq 9+g/2 qi.ymqapge++ (khk grizontal floor with a force of 100 N in a direction of 37.0e above the horizontal. If the mass of the box and the books is 40.0 kg, wh+qiqg p /eaqy+(2g+ hmk9gk.hat is the normal force on the box?

  A traffic light of weight 100 N is suppw8zuz r7z gq46orted by two ropes as shown in Fig. 4-2. What are the g 4 q6zzw8z7rutensions in the ropes?

  In Fig. 4-2, if the tensions in the ropes are 50 N, what is th w8rat/d m/ fp2y1vro+e mass of the traf/rwfr 2md81o+ yva /tpfic light?

  Two boxes of masses m and 2m are in contact qaz hp/qla 2tq7 me98p n(ps7g6c(-sawith each other on a frictionless surface. (See Fig. 4-3.) What is the acceleration of the m(p72 /cnq pz smta9l-qa 8h 6e7(gsqapore massive box?

  Two boxes of masses m and 2m are in contact with each other onw+oj3t/ o wnk17vql7 i a frictionless surface. (See Fig. 4-3.) Wh1vtwwolo7 nq+ kj7/i3at is the net force on the more massive box?

  Two boxes of masses m and 2m are connected by a rope. (See Fig. 4 - ezb1sm:tlbwio() c60khl+a-4.) If the forward force on the more massive box is F, what is the tension in the connectinbc(- t0ia 1:k6l+lsobmhw e) zg rope?

  Two boxes of masses m anw;ljdi f n:rr.c(3re(d 2m are connected by a rope. (See Fig. 4-4.) If the forward forcdf;(l:j3ir(w rn.c ree on the more massive box is F, what is the acceleration of the less massive box?

Two boxes are connected by a cord running ove *x 0pfpko 09eu*7ntdymx01her a pulley as shown in Fig. 4-5. Box I of m*fep09om*du y7 xep 0hn10xktass
8.0 kg rest on the top of the table; the coefficient of kinetic friction between box I and the table is 0.10. Box II has a mass of 15.0 kg.
(a) Draw the free-body diagrams for the two boxes, identifying all of the forces acting on each of the masses.
(b) Calculate the acceleration of the system.
(c) Calculate the tension in the cord.

  The coefficient of static a 8wsx4a+k9j 6:,byx e,sayhrknd kinetic frictions between a 3.0-kg box and a desk are 0.40 and 0.30, respectively. What is the net force on the box when a 15 N horibx9 8a:+y6jy,sea kwk,s 4rxh zontal force is applied to the box?

  The coefficients of static and k rd7 xx ; p18ogxrkk /e80ug,h9im1jjqinetic frictions for plastic on wood are 0.50 and 0.4j px8h 7x i9eo1r,kqx0 8jdr/;gmu1 gk0,
respectively. How much horizontal force would you need to apply to a 3.0 N plastic calculator to start it moving from rest?

  An object slides on a level surface in the +x direction. It slows and comes txqo7jxgo:zna x )vi9:q8 byhk3( wl56o a st3 q bxlyoongq6i:hwzx a5(9kx8 j7v:)op with a constant acceleration of -$2.45 \; m/s^2$. What is the coefficient of kinetic friction between the object and the floor?

  A 10-kg box sitting on a horizontal surface is pullf2vs ,pouo7-ted by a 5.0-N force. A 3.0-N friction force retards the motion. What is the accelerati-o7vs pf2ut,oon of the object?

  A horizontal force of 5.0 N accelerates a 4.0-kg mass, from rest, at a rm-ljv27n kpm5 jeb0*iate of $0.50 \; m/s^2$ in the positive direction. What friction force acts on the mass?

  During a hockey game, a puck is givenx2 xr c6/ tlzoww.i(.+l kc4ro an initial speed of 10 m/s. It slides 50 m on the ice before it stops. What is the colxo (c c2kr4/ l+.zrxowt6w.iefficient of kinetic friction between the puck and the ice?

  During the investigation of a traffic accident, police find sk hplkco/i2vjguhq,g/6 ;( 0y mo-v+lkid marks 90.0 m long. They determine the coefficient of friction bej - o; vmg(y/ uk/vpg,q6llo0ihh+ck2tween the car's tires and the roadway to be 0.500 for the prevailing conditions. Estimate the speed of the car when the brakes were applied.

  Two boxes of masses 7py,kk0pfm*hjal sp+j3. fh85 qh:bc m and 3m are stacked. (See Fig. 4-6.) The surface between the more massive box and the horizontal surface is smooth and the surface betwe05hkhpk7cm p: s, a l3+*hff.pyb8jqjen the boxes is rough. If the less massive box does not slide on the more massive box, what is the static friction force on the less massive box?

  Two boxes of masses m an7i)foj ; c)jv9dmtei;i0 ,sgld 3m are stacked. (See Fig. 4-6.) The surface between the more massive box and the horizontal surface is smooth and the surface between the boxes is rough. If the less massive box does not slide on the more massivms ilfij;)o9g vtji70c;) ed,e box, what is the coefficient of static friction between the boxes?

  An object is on a frictionless inclined plane. The plane itp r1rt*ccly qph 0i( ,6mvq7+.gqe-ms inclined at an angle6tp 0r ,1i -qr+ey .qlmq(hvc*t cpgm7 of $30^{\circ}$ with the horizontal. What is the object's acceleration?

  A 10-kg mass slides down a flat hill that makes an 4xq3(ysn0v3o t;98 tiiwn ywu angle of $10^{\circ}$ with the horizontal. If friction is negligible, what is the resultant force on the sled?

  A mass is placed on a smooth inclined plane with an anpzgh/ ) f; ;rvus5b8.ezjh +mggle of $37^{\circ}$ to the horizontal. If the inclined plane is 5.0-m long, how long does it take for the mass to reach the bottom of the inclined plane after it is released from rest?

A block lies on a smooth inclined plan6.i*a1et cp*f xjib;ze tilted at an angle of $35^{\circ}$ to the horizontal.
(a) Draw the free-body diagram for the block.
(b) Determine the block's acceleration as it slides down the inclined plane.
(c) If the block started from rest 8.5 m up the incline from its base, determine the block's speed when it reaches the bottom of the incline.
(d) How long did it take the block to reach the bottom of the inclined plane?

  A wooden block slides emce3xz4o.wp+3 dm5 (+cicdgby50 r .3y nkdldirectly down an inclined plane, at a constant velocity of + kiz05dmd( ncm3pce533. ry+oxgd4e c.l wby6.0 m/s.
What is the coefficient of kinetic friction, if the plane makes an angle of $25^{\circ}$ with the horizontal?

  An object with a mass m slides do9zge( 0rk- hbpwn a rough $37^{\circ}$ inclined plane where the coefficient of kinetic friction is 0.20. What is the acceleration of the object?

  An object with a mass m slides dowbk7 j )pj8:-fank n(e*mce 9idn a rough $37^{\circ}$ inclined plane where the coefficient of kinetic friction is 0.20. If the plane is 10 m long and the mass starts from rest, what will be its speed at the bottom of the plane?

  A bulldozer drags a log weighing 500 N alonns 1zj md43vs ea-w0a3g a rough surface. The cable attached to tha-s4j 31s3zdam0 new ve log makes an angle of $30.0^{\circ}$ with the ground. The coefficient of static friction between the log and the ground is 0.500. What minimum tension is required in the cable in order for the log to begin to move?

A 25.0-kg box is released from rest on a roy*c1 mna,gfyac p 3c)7ugh inclined plane tilted at an angleymaf,ayp cc7ng)* c3 1 of $33.5^{\circ}$ to the horizontal. The coefficient of kinetic friction between the box and the inclined plane is 0.200.
(a) Draw the free-body diagram for the box.
(b) Determine the force of kinetic friction acting on the box.
(c) Determine the acceleration of the box as it slides down the inclined plane.

  An object is placed on an inclined plane. Thyp-6r m2k kmq9e angle of incline is gradually increased until the object begins to slide. The angle at which this occurs is q. What is the coefficien 9-6prmmqykk2t of static friction between the object and the plane?