Which of Newton's laws best explains why motorists 8m r 8hy*k-oh+m00o r(fpb yqh7ck *xtshould buckle-up?

  When you sit on a chair, the resultant force on mbc pszzpc0*8 v jg ; l3(9wpsp39kd+byou is

  In the absence of an external force, a moving objec o4n2+vhv.)jkok)m c:(hlqrr t will

  When the rocket engines on the starship NO-mc; 4xmsg 5.*,gq+ri (digh 1jdk +zziPAIN-NO-GAIN are suddenly turned off, whi (gir md1;igg+ k+.scm jq*dz4,zxi5hle traveling in empty space, the starship will

  A rocket moves through empty space in a straight line w iv7z z)qy6ez 2lr ,bmzs//n9kith constant speed. It is far from the gravitational effect of any star or pla2 6yb/z7re)z/ilz9mn, kvqs znet. 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 bus, facing forward, and yla:5l *vaqi7you suddenly fall forward. You can imply from th 5l:yaa i*7vqlis that the bus's

  You are standing in a moving bus, facing forward, and ; *8un+p wic) yne rc.av.;8bcyaoz*n you suddenly fall forward as ;yzb w8ev *.cpr+anc*)c ;oanny.u8i the bus comes to an immediate stop. What force caused you to fall forward?

  A constant net force af-hb l1m zqt65cts on an object. Describe the motion of the object.

  The acceleration of ann9gz 3x-3dxu2ivs4sy5 *c b dw object is inversely proportional to

  A net force F accelerates a mass m with an accelerata c).udn ;eq. ;n4l;j*cqhsq kw8jab6ion a. If the same net force is applied to mass 2m, then the acceleration will be ).c wk4;.l6;8a j *jcn;qheasdquqnb

  A net force F acts on a mass m and produces an acceleratok2e b(hg,x/ tion a. What acceleration results if a net force 2F acts on masso eb gkt2,(h/x 4m?

  If you blow up a balloon, and then release it, the balloon ze(v -v:h da4 :ygfgk.will fly away. This is an illusefgk:ah( vvz:yd4 . -gtration of

  Two cars collide head-on. At every moment during the collision, the magniak kir4p;u8o k6kq 33xfzd 6+btude of the force the first car exerts on the second is exactly equal to thz3x+ fk4u3i kbkpro;d86a6kqe magnitude of the force the second car exerts on the first. This is an example of

  If you exert a force F on an object, the force which the object exerts on7 /2ns)huprn o;f 32deodlu 1 bb;ghomhy) 1p3 you wi7;h12p1n e3p3hrh l d)gfmsuood;2uby/ )o nbll

  Action-reaction forc 7lf;5zvc d.wo* .f0 0dm;bckd h q-fxly+v.gmes

  Action-reaction forces p+,uco i+c0nhe r2;*yra k 9mvare

  A 20-ton truck collides with a 1500-lb iwv7*)g4 *rq :7y0 ldpjnmikncar and causes a lot of damage to the car. rvi yk4pq*nj iwg:nm l0*d77) Since a lot of damage is done on the car

  An object of mass m sits on a flat table. Thef y:)ff8 gkrytd/ny81or xc;) Earth pulls on this object with force mg, which we will call the action force. What is thegf)yy;f yn)o8/1cdxk:tr f 8r reaction force?

  A child's toy is suspended from the ceiling by means of a so duz x33*pll*tring. The Earth pulls downwa z*ol*ldxu33p rd 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 instantaneous force.clh rzj8 riju ((m*qd/-n1u v: The ball hits the bat with an ijh(q 81 m*-cnrduu(z: li vr/jnstantaneous force, whose magnitude is

State Newton's three lawsz sstf*lbw2 p6uz7u9mzf :,gdo : af.*.

  Mass and weight

  The acceleration due to gravity is lower on the Moon than on Earth. W. ,cahyvhjh4)x /( b:cuzl9-nt v1euuhich of the following is true about the mass and weight of an astronaut on the Moon's n/-ub4 ,ujc(l:tyux z a chh )19hev.vsurface, compared to Earth?

  An example of a force wxj6l3e zfgy1(j2vr4r xsd . (ghich acts at a distance is

  Who has a greater weight t ycc zo(,,e)foo mass ratio, a person weighing 400 N or a person weighi yo,ec,zoc)(fng 600 N?

  A stone is thrown straight up. At the top of its path, the net force acting *qc1i ir-y2t kon ik1t-yc *riqi2 t is

  A 20-N weight and a 5.0-N weight are drotus-m 42a1.ajzvt4r3h -gmi wpped simultaneously from the same height. Ignore air resistance. u-1jzatv4t-hm rmw 3sa 2i4.g Compare their accelerations.

  A brick and a feather fall to the earth at their respective 0 1w+cnc 0fnlgterminal velocities. Which object exwn +l0ncc0fg 1periences the greater force of air friction?

  An object of mass m is hanging by a string from the ceiling of an elevx p-wl,/1eqlvn o6n 5bator. The elevator is moving up at constant speed. What is the t vqxn-1/w,nllo5 6bpeension in the string?

  An object of mass m is hanging by a string from the ceiling of an* ( mtyb2*nf5yk.lhgy elevator. The elevator yfn gmty *b(h *k2ly.5is moving upward, but slowing down. What is the tension in the string?

  The force that keeps you from sliding on a 7 idldg dvr;,7xvuwc4 ljy3*+n icy sidewalk is

  It's more difficult to start moving a heavy carton from rest ti (:krr*(pdav han it is to keep pushing it with constan*pra k(v :i(rdt velocity, because

  A horizontal force accelerates a box from rest acram3l74ava *d eoss a horizontal surface (friction is present) at 4avd7* aa lm3ea constant rate. The experiment is repeated, and all conditions remain the same with the exception that the horizontal force is doubled. What happens to the box's acceleration?

  A packing crate slidhg9vx8vwna a .7cs9 i9es down an inclined ramp at constant velocity. Thus we can deduce av.i98hgn7 9wv cxa9s that

  A block of mass M slides down a frictionless plane inclineqpg/ e5i+v6p jb3 sjn2d at an angle q with the horizontal. The normal reaction force exerted by the plane on the block b65 ip/2+ nsgvjq3jpe is

  A block of mass M slides down a frictionless plane inclined at ma;xft2e 42f gan angle q with the horizontal. The normal reaction force ex; 4tfx22afegmerted by the plane on the block is directed

  A block of mass M slides down a ;q*o;- wl mvxzco7-en,ii f.zfrictionless plane inclined at an angle q with the horizontal. The gravitational force xfioce-7,. w qvzz ;;i -o*mlnis directed

  Two toy cars (16 kg and 2.0 kg) are released simultaneously on an incvt1a -hxh+i:c3hhkm. f3q tj(lined plane that makes an angle of 30e with the horizontal. Make a statement whi1kah h.cm x+t vq3 j:ih3tf(h-ch best describes their acceleration after being released.

  An object sits on a frictionless surface. A;7:cl uab,qiw 16-N force is applied to the object, and it accelerates at b; qa w7u,:ilc$2.0 \; m/s^2$. 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. What2ch:hn kd8l;k 6hm 8hs is the average forward force lhh2nd6h8km;8sh:k c on the car?

  Starting from rest, a02dfvwj+w o g2 4.0-kg body reaches a speed of 8.0 m/s in 2.0 s. What is the net gv20wwjf 2+od force acting on the body?

  An antitank weapon fires a 3.00-kg rocket which acquires a speed of 50.0 m/ u ve2o/favcbh.r.y4 g5o(ge8s after travelin2fvu.b. o ery( g58evg4caho/g
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 thm/jqsn5 n(a o5;lbr0boou-. xat you push a 10-kg mass from restsrbxolna5buq no5( o j 0m.-;/,

  What is the mass of a persoivww,l.qqoal*uhgt5;g7l o7r(t j (3 n who weighs 110 lb?

  What is the mass of an object that weighs 250 N on the surfv1h3i9o1z, *rp ld4mqlrgk x;(rpl)e ace of the Earth where the acceleration due t)rk,o3grpel ;(1* m1l hzplq9r v4dixo gravity is $9.80 \; m/s^2$?

  An object has a mass of 60 kg on th )flqpwu7mgwk 95n) t6e Earth. What is the mass of the object on the surface of the Moon where the acceleration due to gravity is only 1/6 of that m)wk7wfup gl65q t)9n on the Earth?

  Object A weighs 40 N on Earth, and object B weighs 40 N on the Moon. The Moon'2ve0j 6ew qdt*s gravity is one sixth 06eqvwej* td2 of Earth's. Compare the masses of the objects.

  Sue and Sean are having a tug-of-war by pulling on opposite ends of a 5.0o)a.wjkz1- qs -kg rope. Sue pulls with a 15-N force. What is Sean'kw qj1z.) aso-s force if the rope accelerates toward Sue at $2.0 \; m/s^2$?

  A stack of books rests on a level frictionless surface. A force F ac onwhze5o ghd((k,f( nf13t:lj7q 8hlts on the stack, aojf 8d(7 efh(h5h ,g1nnz(k 3ql: woltnd it accelerates 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 du(:k j 85ezv 0i4sse9xhy cxz0geq.6 elevator. What will the scale be reading when the elevator is accelerating dowciz6sq eedk z(v09. jx5ug h48eys0 x:nward at $4.00 \; m/s^2$?

  A person on a scale rides in an elevator. If the mass of the pw-psfn0*9h) t zakt+ierson is 60.0 kg and the elevator accelerates downward wizht)-+*k90in a twfsp th 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 i3twj8kp0n .qk s 60.0 kg and the elevator accqk k n3.t8jpw0elerates 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 ha fg +of6n b dac3;m(y -cyx5.+9yxjnhws a magnitude of 8.0 N and is di3x+gocyynyj.nd9 ca+5f hm;6x w (-fbrected due north. The second force toward the east has a magnitude of 6.0 N. What is the acceleration of the mass?

  An object of mass 6000 kg rests on the flatbed of a truck.sh/ lxt37s s aoyo+p2- k4dbw, 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 distance if th23 hsosaypx 7w-/,to4skl+d be load is not to slide forward into the cab?

  An object of mass 6000 g6t jam;/)rf bkg rests on the flatbed of a truck. It is held in place by metal brackets that can exert)mb/t;f gj6a r a maximum horizontal force of 9000 N. When the truck is traveling 15 m/s, what is the minimum stopping time if the load is not to slide forward into the cab?

  In the Atwood machine shown in Fig. 4-1, if M = 0.60 k g kfqa/q/;ig0zdy,+vk,: calg and m = 0.40 kg, what is the magnitude of the acceleration of the system? (Ignore friction and the mass of the pulley.)gfv ;aaklg:,/c+qy z q ,dk0i/

  In the Atwood machine shown in Fig. 4-1, if M = 0.60 kg and m = 0.40 kqwvqz32t, 9:nmzl n6y(uhdkb xf9 s; ,g, what is the tension in the str2 uyn z ,xkqbtmdwz9 s,q(hv 6f;3n:9ling? (Ignore friction and the mass of the pulley.)

  A student pulls a box of books on a smooth t-gi.qes.n h3zdp c+4horizontal floor with a force of 100 N in a directie+nzti.s hgq.3 cdp4-on 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 horizontal floor with a force oe4fiq4mu1 er( f 100 N in a demfi4r(uqe14 irection of 37.0e above the horizontal. If the mass of the box and the books is 40.0 kg, what is the normal force on the box?

  A traffic light of weight 100 N i ym;i8up yxt5-s supported by two ropes as shown in Fig. 4-2. What a-xupy;y 5tim8 re the tensions in the ropes?

  In Fig. 4-2, if the ten/,z vagkuiz,0l -azu pi)q9jvnp 7xi7ph6)r)sions in the ropes are 50 N, what is the mass of the trafficu,6k77apg p u v)ixn)0r-z),9q /ph jiz iazlv light?

  Two boxes of masses m and 2m are in contact with each other on a frictio3 ,94hrqmav( ktpb +mqnless surface. (See Fig. 4-3.) What is the acceleration of the more massive box?rhb,49at 3+pkm qv(qm

  Two boxes of masses m and 2m are in contact with each other on a dzdld 6oeu,n90 9z1rc frictionless surface. (See Fig. 4-3.) What is lde96r1 dnud c z,z0o9the net force on the more massive box?

  Two boxes of masses m and 2m are connected by a rope. (See Fig. 4-4.) If thennsg;k7v6l 11 zhta 8d forward force on the more massive box is F, what i6a17dt; nl 8gkv1szn hs the tension in the connecting rope?

  Two boxes of masses m and 2m are connected by a rope. (See Fig. 4-4.) If zciz z07t63nz dez4z6s0ki;(/ np vjkthe forward force on the more massive box kke;di0z4t s/0jpzzv6zzi3 (n6 nz7c is F, what is the acceleration of the less massive box?

Two boxes are connected by a cord runnid67ps2ggr (sg+ fpvby f3v06kng over a pulley as shown in Fig. 4-5. Bok (dsfbyv02gf7gp3sr +vp g6 6x I of mass
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 and kinetic frictions between a 3.0-kg box anbqj6qbm gm7lx) .o5 2kp l34pzd a desk are 0.40 and 0.30, r.zp mgol )pjbq5x34 k7b6lq2mespectively. What is the net force on the box when a 15 N horizontal force is applied to the box?

  The coefficients of static and kinetic frictions for plas-qy7ac fcx 7cc yzw-:i)9o.zx/ixu/ rtic on wood are 0.50 and 0.40- :xwy rx/ cz7o9q.ciixu / ac)f7z-cy,
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 in4nyfjd,xzu 2(9 g)y 4pdw v5br the +x direction. It slows and comes to a stop with a constant accelngyu9p,) zdrbxfdwy (45j42veration 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 lj7t*zp +3eil/h 1pa q oscw6wj-)rh 5a horizontal surface is pulled by a 5.0-N force. A 3.0-N friction force retards the motion. What is the acceleraw6+*s/ih 5 -r potp1hwe7q)lj jzc3altion of the object?

  A horizontal force of 5.0cj q 7qko;ni,) N accelerates a 4.0-kg mass, from rest, at a rate of $0.50 \; m/s^2$ in the positive direction. What friction force acts on the mass?

  During a hockey game, a puck is given an initial speed of 10 m//e p*lst -5e,np7diqws. It slides 50 m on dwls-p7 /* inpe5e q,tthe ice before it stops. What is the coefficient of kinetic friction between the puck and the ice?

  During the investigation of a traffic accident, police find skid marks 90 )jotbo(atc4 1.0 m long. They determine the coefficient of friction betw)tooct (bja 41een 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 m and 3m are stacked. (See Fig. 4-6.) The sofnpp1bz 6i y2e1;w2; 3pve ncurface between the more massive box and the horizontal surface is smooth and the surface between the boxes is rough. If the less massive f n 2yp zie1b61;ec pw2p;o3vnbox does not slide on the more massive box, what is the static friction force on the less massive box?

  Two boxes of masses m and 3m are stacked. (See Fig. 4-6.) The surfky--l0 jiw z3ap0n 1eeo*7nlcace between the more massive box and the hza0 j *i-l p1l yc7wnk-3eoen0orizontal surface is smooth and the surface between the boxes is rough. If the less massive box does not slide on the more massive box, what is the coefficient of static friction between the boxes?

  An object is on a frictionless inclined plane. The planlhh2kj( tavf /y8(4w be is inclined at an angle of l(wbhhav kf4 t(2yj/8 $30^{\circ}$ with the horizontal. What is the object's acceleration?

  A 10-kg mass slides down a flat hill that makes an an5t.y j w2kv7 kw/ ki.,0 ggoy-kenmu6,*r gxdxgle 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 an- 4v rtd86al;xfl grl(gle 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 pla. w7l(u tdlnmlr)9 ff:ne 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 directly down u( ll9sr-, rbm6llkd9 an inclined plane, at a constant velocity of 6bmd l6-r9(k ll,u9s lr.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 o: 93boxb+7z+u/e4d5m - enypimawsp slides down 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 down a ro x7q5i vs8aopdg gp29*ugh $37^{\circ}$ 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;fgzr)t l,k y* along a rough surface. The cable attached to the log makes an anglerl kfz*y)g ,t; 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 fro68t8zzb dtozp3xr r4y7a9.y em rest on a rough inclined plane tilted at an angle of tr.yyz o p3 ez8x 8tbz94ra76d$33.5^{\circ}$ 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 arjleo p -q5qz( i7-s/zn inclined plane. The angle of incline is gradually increased until the object begins to slide. The angle at which this occurs is q. What is the coefficient of e i5 (q7 rqls-j/-pzzostatic friction between the object and the plane?