Which of Newton's laws best explains why):fuy,3zpo medr4 ,o i motorists should buckle-up?

  When you sit on a chair, the resultant force on you xxz1, ggb-qty 8oz 0*qis

  In the absence of an exterv l,;xs/t ih1vnal force, a moving object will

  When the rocket engines on the starship NO-PAIN-NO-GAIN auaci-7:twr5ut ti0 yj 5 /hd2are suddenly turned off, while traveling in empty cida:5a th7y2i5u -jw u0/ttr space, the starship will

  A rocket moves through empty space in a straight li hmkuf1r )-8zyne with constant speed. It is far from the gravitational effect of any star or planet. Under these conditionsym)h k- z18fur, the force that must be applied to the rocket in order to sustain its motion is

  You are standing in a moving busf8q2y 4e(kpc u6(ndidbb;l,yxs* u(b, facing forward, and you suddenly fall forward. You can i8end;fi2q ubs(k y6d x( bb4pl(cy *u,mply from this that the bus's

  You are standing in a moving bus, facing forward, and you sud-+yt *yubt3.g ka+vqodenly fall forward as the bus comes to an immediate-*gq+ ty+v3o .kbauty stop. What force caused you to fall forward?

  A constant net force acts on an object. Describe the motion of the object. )pu)3+furd)uyl (hqr

  The acceleration of an object is inversely proporti alkhr ;.lu(7svqi:+ional to

  A net force F acceleratef+0q loi-y+ uvs a mass m with an acceleration a. If the same net force is applied to mass 2m, then the acceleration wu-+of0+i q lvyill be

  A net force F acts on a mass m and produces an acce91j2mdb fc-* m7anf);.hrk up,ty mgy leration a. What acceleration df- khyy)m .tn9bu7r;1mcpmj ,2f *ga results if a net force 2F acts on mass 4m?

  If you blow up a balloon, and then release it, yad3pqtw 85w .the balloon will fly away. This is an illustrat53ptqda8 w.w yion of

  Two cars collide head-on. At every moment duringvicu22onx2 8u the collision, the magnitude of the force the first car exerts on the second is exactly equal to the magnitude of the force vu2o 2n8 x2iucthe second car exerts on the first. This is an example of

  If you exert a force F on an object, the force which the objeqo5s8fi* -qzh ct exerts on you wis i*- q8q5fhozll

  Action-reaction forc vx *(/mng5ityes

  Action-reaction force)sw8bmc/z9x 1l1xt l k ;-ixb, lewjw.s are

  A 20-ton truck collideyitb+ q+2kwg* s with a 1500-lb car and causes a lot of damage to the car. Since a lot of damage i gw +yibtq+k2*s done on the car

  An object of mass m sits on a 4ytink,i q+fa:r5uz7 flat table. The Earth pulls on this object with force mg, which we will call the action force. Wqzut,i5+4nk: y7ra fi hat is the reaction force?

  A child's toy is suspended from the ceiling by means of a string. The /vfe/vv(vd:q6pzw e 6Earth pulls downward on the toy with evf6vq: ( p6wdvz/ve/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 inst44-mlczjaljo+ 0k18fdvkq5t antaneous force. The ball hits the bat wit5j1l kk40j cf8vqloatm z -4+dh an instantaneous force, whose magnitude is

State Newton's three ldnwo cz1g-g:p2vz9 g: aws.

  Mass and weight

  The acceleration due to gravity is lower on the Moon tr:sq+he 2zn :ehan on Earth. Which of the following is true about the mass anz:eqr:e +ns2 hd weight of an astronaut on the Moon's surface, compared to Earth?

  An example of a force which acts avinvflx3q,075gly+r 39 np f1tkn2mnt a distance is

  Who has a greater weight to me.oikednz90zink 4vui 0 c16xs(h gp+j*jv76ass ratio, a person weighing 400 N or a person weighing 600 i.igjznxk 4p6vekn0e7vdj z 0o 9*1c+u(s6hiN?

  A stone is thrown straight up. At the top of its path, the net force acting z,*z u4yeki d.on it iy*.zdkzu 4e, is

  A 20-N weight and a 5.0-N weight are dropped si ns9 br,dl:n/q(i7vjrz kzl(,dcj/h4multaneously from the same height. Ignore airnd4hisqjn(,dzcv7/k,(j9: rl b/rzl resistance. Compare their accelerations.

  A brick and a feather fall to the erq-a6ad+4tpe arth at their respective terminal velocities. Whicd4 t-6aaep+ rqh object experiences the greater force of air friction?

  An object of mass m is hanging by a string from the ceiling of an elev*i q:9y )v tyy86sdzfgy00 horator. The elevator is moving up gd0 y*6f tsy)v90yr8hzqy i:oat constant speed. What is the tension in the string?

  An object of mass m is handyxxt;9 i(y0gb ;hm+ajn:*dz(gip w 3cyy, ,d ging by a string from the ceiling of an elevator. The elevator is moving uhy;9*+,byg(ixd0yz cpn at;d,:m3 xd ( iwjgypward, but slowing down. What is the tension in the string?

  The force that keeps you from sliding on an icy *z+agh5 pft ;r +ym)basidewalk is

  It's more difficult to start moving a heavy carton from rest kp0p0uoj.j,b38l+h 9 snzntsthan it is to keep pushing it with constant velocity, sl bj.+up903,zktnhsj p no08because

  A horizontal force accelerates a box from rest across a horizontal surface (frs+pzg5b 8hzy63r.*jw -l rnvkiction is present) at a constant rate. The experiment is repeated, and all conditions remain3gbzn6vw8jk5+ r*y rl -h.ps z the same with the exception that the horizontal force is doubled. What happens to the box's acceleration?

  A packing crate slides down an inclined ramp at constant velocit1o0runkw m)t7j 0.k;ftbx w. qy. Thus we can deducef0t j1 uw;kwbm.n0) x kr7t.qo that

  A block of mass M slides dowd 7s(t.k -vnkyj2 :eey h7i.wbn a frictionless plane inclined at an angle q with the horizontal. The normal reaction force exerted by7.d jy 7: n(htsi v-ybk.2ewke the plane on the block is

  A block of mass M slahe/ zb,qa9ds,u69)n h 5mfzhides down a frictionless plane inclined at an angle q with the horizontal. The normal rea/,aa6 z hun5)m bszq9eh9,d fhction force exerted by the plane on the block is directed

  A block of mass M slides down a frictionless p4:ayutnq y; d9lane inclined at an angle q with the hor n;y4:a9qt dyuizontal. The gravitational force is directed

  Two toy cars (16 kg and 2.0 kg) are released simultaneously on apop6y eq,pxl ,e 6p6;cn inclined plane that makes an angle of 30e with the horizontal. Make a statement which best deq pe,lyep o,6;cp6px 6scribes their acceleration after being released.

  An object sits on a frictionih2d5pn7b 2jnh5rc s, 4ppz8 uless surface. A 16-N force is applied to the object, and it accp,82pzhd5nc 4pnj b hius2r57elerates at $2.0 \; m/s^2$. What is the mass of the object?

  A sports car of mass 1000 kg can accelerate ; fhm3y4npyh47u ag4pbl-s 9xfrom rest to 27 m/s in 7.0 s. What is the average forward force on the cagh x7y;f4n lpu 3s49yp4b-ha mr?

  Starting from rest, a 4.0-kg body reaches a speed of 8; ko3w *uzdg;twc5w4i .0 m/s in 2.0 s. What is the net force acti 3 cgkw*t45;wdiwozu ;ng on the body?

  An antitank weapon fires a o i3od6 chfb7 fjzfc*q0g(,h .3.00-kg rocket which acquires a speed of 50.0 m/s after traveli ,.h6ofdb(qg f*f c0j7o3zich ng
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 majn+w79w 2nsxh9c2s /qy ) rhunss with the same force that you push a 10-kg mass from renn w /7qrjn9)sh 2whcuxy9+2sst,

  What is the mass of a person who wes6x, nkm8ym/cu /cfn 47z8 ioeighs 110 lb?

  What is the mass of an object ag 4sc9;d pu3j-quqs(that weighs 250 N on the surface of the Earth where the acceleration due to gravity isp-jcuds;4 uqq3g9(s a $9.80 \; m/s^2$?

  An object has a mass of 60 kg on the Earth. What is a- qt;:rz ii+mthe mass of the object on the surface of the Moon where the acceleration due to gravity is only 1/6 of that on the mzir:aq; -i +tEarth?

  Object A weighs 40 N on Earth, and object B weighs 40 N on theszv6z +e wl-qhb71; + tniosh3 Moon. The Moon's gravity is one sixth of Earth's. Comparhe+ihv-71 6zqw3 o s n+sblzt;e the masses of the objects.

  Sue and Sean are having a tuk (o9r;s sfd4rg-of-war by pulling on opposite ends of a 5.0-kg rope. Sue pulls with a 15-N force. What is Sean's k;(rd9f4sr os 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 Fb x6y 9dpcczokr+ /5th2yd;s qt4-bf- acts on the stack, a;6 o/t 5y t-dhb frsq-pd2cb9kc4xz+y nd 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 elevator. What will tb os8mjj3 n 45a4w8f-q /ordaxhe scale be43a 5waq/sx8ro-jjmnf d8o4b reading when the elevator is accelerating downward at $4.00 \; m/s^2$?

  A person on a scale rides in an elevator. If the mass of the person is 6ge oef0w-n0fnlixhl9 /9q,s; 0.0 kg and the elevator accele glw,qen0sfnehfl o/x9-09;irates 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 is 60.0 kanys- n6tdxb r6qu1 6b7n; 4pyq/nct9g and the elevator accele1x-npusnty dyc;t6nr9 ba n/q6467qb rates 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 h vj ntd63i;mqg j7l.m9as a magnitude of 8.0 N and is directed due north. The second force toward the east has a magnitude of 6.j7 v 3; d6jq.9mtnimgl0 N. What is the acceleration of the mass?

  An object of mass 6000 kg rests on th4umq5nkp 1r5/-(f6 yytyacji+ jn4c f e flatbed of a truck. It is held in place by metal brackets that can exert a maximu 4nj1m 6ify5 yrkuj-4ty5aq+f/c cnp(m horizontal force of 9000 N. When the truck 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 rests on the gomk0-cfo;/-mko .dah 5dr-cflatbed of a truck. It is held in place by metal brackets that can exert a maximum horizontal force of 9000 N. When the truc0omcf o-- /5dakh .cd-o;kmgr k 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 hwvy95sys3 lys)/l/ wbzf( ,yin Fig. 4-1, if M = 0.60 kg and m = 0.40 kg, what is the magnitude oyb/wsf5 y9,v()wly h/s ylsz3 f the acceleration of the system? (Ignore friction and the mass of the pulley.)

  In the Atwood machine shown in Fig. 4-1, if M = 0.60 kg and m = 0.40 kg, what is/h4n jy6q,r/px-posb the tension in the string? (Ignore friction and the mass of thxq s6jnp p yor/h-4/b,e pulley.)

  A student pulls a box of books on a smooth horizontal floor with a force of 1 rd-6)g lyzft, gt:t3c00 N in a directirtgf lyg d):6t 3z,tc-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 hod7l xqzge( oq5i,a0t5rizontal floor with a force of 100 N in a direction of 37.0e above the horizontal. If the mass of the box and th z(g57 5,odqtalx qie0e books is 40.0 kg, what is the normal force on the box?

  A traffic light of weight 100 N is supported by two robn0*e egf9,b vpes as shown in Fig. 4-2. What are the tensions in the r 9*be0ebnfgv ,opes?

  In Fig. 4-2, if the c2(g0g jp qei8v3dh ,wtensions in the ropes are 50 N, what is the mass of the traf30g8hcd p iewj gq,2(vfic light?

  Two boxes of masses m a+bq: zqd6 nga;s: /xqgnd 2m are in contact with each other on a frictionless surface. (See Fig. 4-3.) What is the acceleration of the morg x6db+:s/zn;qq q:ag e massive box?

  Two boxes of masses m and 2m are in contact wi 1u3e njslz7k9th each other on a frictionless surface. (See Fik n3l7zjs1u9 eg. 4-3.) What is the net force on the more massive box?

  Two boxes of masses m and 2m are connecx; 7xd;h tlbdl4gurv/5/ hv s:ted by a rope. (See Fig. 4-4.) If the forward foh 4/r:/;vvts7 x 5l xgb;dluhdrce on the more massive box is F, what is the tension in the connecting rope?

  Two boxes of masses m and 2m + 3 mp oo8ak.)v9ywd/3qmqbze) wvr, gare connected by a rope. (See Fig. 4-4.) If the forward force on the more massive box is F, w)9.wzd3, wmv b pq+8v/qaokg3m yr )oehat is the acceleration of the less massive box?

Two boxes are connected by a cord running over a pulley as shown in Fi/ ph :2kx1gybcg. 4-5. Box I of mass hcyb2 xk/:gp1
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 bons15jf- g/-wp:7sjmj (h lr fbx and a desk are 0.40 and 0.30, respectively. What is the net force on the box when a 15 N horizontal force is applied to the b1l(b5rjhfw7p gj:sj s/nm- -f ox?

  The coefficients of static and kinetic frictions for plastic on wood are 0.50 an:pm.k -szo6by jw5/ ;ovx d1vr)*swy ud 0. mw6v dos. os;/y1y-rpxzub:)j5kw v*40,
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 e: a5m7bi- s; pu*cfkgfm,aa3os6i /p.+xrvfin the +x direction. It slows and comes to a stop withvkimxe gb3fou i 6 ascpam:/s7f.-,5; a*f+r p 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 pulled by a 5.0-N force.e)xq fpq(vh3 + A 3.0-N friction force reta(e3)xf+vhqq prds the motion. What is the acceleration of the object?

  A horizontal force of 5.0 N accelerates2r w1cxwy* y8n 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 a76bbfhmzx2wbbsc:*w)2 ilj.g wi3vco 7-3/s. It slides 50 m on the ice before it stops. What is the coeffici)c7 j3 v*e-23g7:bbwol b .mwxszw2cfa bh6iient of kinetic friction between the puck and the ice?

  During the investigation of a traffic accident, police find skid yz9mhsuh tl:z194 (a kmarks 90.0 m long. They determine the coefficientk h(l91zu yzms tha:94 of friction between 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. iej:pgqo-f9h .k0/ mc 4-6.) The surface between the more massive box and the horizontal surface is smooth and the surface between the boxes is rough. If h. ci0po /9egm-qf:kjthe 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 and 3m are stacked.5srom(( :wc2lofd ad. (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 massive box, what is the coefficient of static friction between theld( o(m2doa :frs 5.wc boxes?

  An object is on a frictionless inclined plane. The plane is inclinedf: ,s3r+kik+ n b8feqvx/,jr k at an angle ofs:k/q,+b 3f+, fi8nkvxkerrj $30^{\circ}$ with the horizontal. What is the object's acceleration?

  A 10-kg mass slides down a flat hill that makest)tvhg.rv (c 5 an 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 ;pkm)3hc6 e6ns wysl 4smooth inclined plane with an angle 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 smootikgaxya)mx, h:(lsfscq), 8pi 3t 0z/h inclined plane 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 an inclined plane, at a constant velocivyvoc41dq5) ety ofc5 edo4 qyv)1v 6.0 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 down a0xql.iqc3 mc8hm4d+z 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 slides866jajg.s*yz zy,3xge * xuxx down 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 50 t.(oqu)u usa.fsko20 0 N along a rough surface. The cable attached to ta tkuuos.q. 0us2f) (ohe 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 rough inclined plane tilte -u5jx6e k*rlsxou l+.d at an angle ofx.sxlok6u -l u*ej+5r $33.5^{\circ}$ 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. The angle oolux0u 9jto 35 ,ipo6of incline is gradually increased until the object begins to slide. The angle at which this occurs is q. What is the coefficient of static friction between the oji l uoo0po 35,6tuo9xbject and the plane?