Which of Newton's laws best explains+:4goj 7oy ,xevdj6t b why motorists should buckle-up?

  When you sit on a chair, the resultant focoue.m g4/dhh5d r :i)p+d)mv(i:e dsrce on you is

  In the absence of an external force, a moving object wi-e3ex p/w a+skpic2+ull

  When the rocket engines on the starship NO-PAIN-NO-GAIN are suddenly turpkx56 ulfb(m 7ned off, while traveling inx5klu6m 7b pf( empty space, the starship will

  A rocket moves throug( (+fqj.nibf:f5usldh empty space in a straight line with constant speed. It is far from the gravitational effect of any star or planet. Underqlfuf 5(ni+j(fsbd: . 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 fort,gihhyj- ij,pp )s 37ward, and you suddenly fall forward. You h3h7 ,j ,i isj)-ygtppcan imply from this that the bus's

  You are standing in a moving bus, z 4)2ls dia/d 6/9kde jdlzwwdg)jn0gg+q;7u facing forward, and you suddenly fall forward as the bus comes todldd aj)/ d2qn+0wz) l9k e g/jdw iug;zsg467 an immediate stop. What force caused you to fall forward?

  A constant net force acts o):vvbm j r*2 w5) uijze2bsw)cn an object. Describe the motion of the object.

  The acceleration of an object is inversely proportiol6 j3e att3apo 8hw :4u(jtlk-nal to

  A net force F accelerates a mass m with an accele)n o4p5h)wrlevscz1 +ration a. If the same net force is appsw)cohpz4e vn+ )lr15lied to mass 2m, then the acceleration will be

  A net force F acts on a mass m and produces an acceleration a. What accelera91yf- b4r-dlukqk() adno 21seh7s gxtion results if a net force 2F acts ons)(9f -hd xqy-sgr kk ub1eo721ad4nl mass 4m?

  If you blow up a balloon, and then release it, the balloon wilk d027xsgai4el fly away. This is an illustrat4x ei2sg k0da7ion of

  Two cars collide head-on. At evv,1wvfyytn k h 4oi:* j4uk:p6ery moment during the collision, the magnitude of the forceh : kojkt,1vuvw yi:f44 py6*n the first car exerts on the second is exactly equal to the 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 thj lk at+.,r 44vf g90rhit.lmcego;8he object exerts on you wiv g4,4lml.e9ja8f.; k ogi0ctht+r hrll

  Action-reaction forceb;g00 pif hwy;uzob;91 sbih )s

  Action-reaction forces ar w v8qes(0b1cjcbxbc(0r (dd2 e

  A 20-ton truck collides with a 1500-lb car and causes a lot of damage0hyz 3obo0:a- n/ piox to the car. Since a lot o-pnh:0 i zao0/o3xb yof damage is done on the car

  An object of mass m sits av146jl ys :0rkmhmk p au3zh.z-ei( 2on a flat table. The Earth pulls on this object with force mg, wu 4h mmvz k1ie.s2-aja y0p63lzk:(rhhich we will call the action force. What is the reaction force?

  A child's toy is suspended from :z5sq6pfyc 8uut d8t/the ceiling by means of a string. The Earth pulls downward on the toy/uy 8d6cpt u:fq5 s8tz 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. T y 4 59q15qagbcn-zeg0j1lggx he ball hits the bat withx-ez5c glgg11g ny9qq j5 ab04 an instantaneous force, whose magnitude is

State Newton's three laz2x)yj;boqb(uyi- t s ql6/,hws.

  Mass and weight

  The acceleration due to gravity is lower on the Moonjuh;e(4slr n 3 dhy10ze5, ura/mp97cv v+jjx than on Earth. Which of the following is true about the mass and weight of an astronaut oyjm; urhc(jan s ,/lz9e+105 pvdu734evhjrxn the Moon's surface, compared to Earth?

  An example of a force which acts at a distan mug9cw*uy, 3nce is

  Who has a greater weight to mass ratio, a personb5l)a-nca 0h o weighing 400 N or a person weighinghaa c o0bl)-5n 600 N?

  A stone is thrown straight up. At the top of its path, the net forcu7pp m7cni ;s-e acting on it isps ;uc7 np7m-i

  A 20-N weight and a 5.0-N weight are dropped simulq-u 9mcr (s4vbtaneously from the same height. Ignore air resistance. Compare theirrmuc-q vs(4 9b accelerations.

  A brick and a feather fall to the evnyw5 tkfwp6 y5/k ;t.-ncb5ofsc,3s arth at their respective terminal velocities. Which object experiences the greater force of airw 3nwts5 y,k5bfy5f - cops.knv/6;tc friction?

  An object of mass m is hanging by a string from t: *r;9vezamal1m4z t nhe ceiling of an elevator. The elevator is moving up at constant speed. znlt r*:aazm 9 41;emv What is the tension in the string?

  An object of mass m is hanging by a string from the ceiling of an (*zo+tdl jtwrhwey25n90- m lelevator. The elevator is moving upward, but slowing down. What is ht+m29l*tl5wowz (dn0y -ej rthe tension in the string?

  The force that keeps you from sliding on an icy sidewalk i*i5l wu00xwvzs

  It's more difficult to start moving a heavy8q .*;ej s (/s*nz*4h hustfnxwk3 rlg carton from rest than it is to keep pushing it with constant velocity 8;ss** s.nx r khn e(g*4wjflzu3qht/, because

  A horizontal force accelerates a box from rest acrosmw x/ez 6.wy5pmbaocc5 /xs.6s 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 horizwc/ewsay.b 5mzm5 c.o6p6 x/xontal force is doubled. What happens to the box's acceleration?

  A packing crate slides down an incg 2c /r,m)rjpx/a r,u2fqlzdyb )3 +gjlined ramp at constant velocity. Thus we can deduce thagf/+ zg,pyr2) /r,c )2 rajj3 mlduqxbt

  A block of mass M slides down a frictionless plane inclined at an angle mu1wc: m(4 (k,u0 zeq qpw1xvdq with the horizontal. The normal reaction force exerted 4cu1 : pmw0q,x(mwzqe vd1uk(by the plane on the block is

  A block of mass M slides down a frictij2x jo t(w. e0np,ko:l3i/oed onless plane inclined at an angle q with the horizontal. The normal reaction force exerted b/0 xjto:e .pol,w(3k e2dn iojy the plane on the block is directed

  A block of mass M slides down a frictionless plane- j.xy x:j2iy4f1 atva inclined at an angle q with the horizontal. The gravita.x vyi2j xt:-yja4 af1tional force is directed

  Two toy cars (16 kg and 2.0 kg) are released simultaneously on an/ -ejgo/jb )gh inclined plane that makes an angle of 30e with the horizontal. Make a statement which best describes tghb) - jg/ej/oheir acceleration after being released.

  An object sits on a frictio6 lm jx)(/ucq:k1bqoonless surface. A 16-N force is applied to the object, qux6)l(cbo/kqo : 1mj and it accelerates at $2.0 \; m/s^2$. What is the mass of the object?

  A sports car of mass 1000 kg can acq +b nb:ipf,fqi3-3 t(i c:wvo 9vqvd)2eg j:tcelerate from rest to 27 m/s in 7.0 s. What is the average forward force on q:2 efvboqfj:3 )iw93qv(pgd-vtb +:, niic t the car?

  Starting from rest, a 4.0-kg body reaches a speed of 8.0 m/wo0(z8zro6:+rtw s q0 pna8 kss in 2.0 s. What is the net force acting on the bowa :06rqn8t k(+zozso 0wprs8 dy?

  An antitank weapon fires a 3.00-kgeqovy5c9 k,owyu /w mh,s)0, orx -;eo rocket which acquires a speed of 50.0 m/s after t,q,-e w oy u 9wk5hoo0;v)xcys eor/m,raveling
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 a 10-kg mass from xz-ig*p3 9 u(c1j0ee5gqoo o nrestge ije9 *co3qug(np5 - oxo0z1,

  What is the mass of a person a (g m-/hpi.wk2m5 s/r xzexjjh.*/rmwho weighs 110 lb?

  What is the mass of an object that weighs 250 N dao tvo 7h)t5;on the surface of the Earth where the acceleration due to gravity 7 att;o hv5d)ois $9.80 \; m/s^2$?

  An object has a mass of 60 kg on the Earth. vcqh-(p4 ar)dzfb(- t What is the mass of the object on the surface of the Moon where the acceleration due to gravity is only 1t-v (p-4 rz ch(dba)qf/6 of that on the Earth?

  Object A weighs 40 N on Earth, and object B weighs 40 N on the Moon. The zi(ql.gzm x c/jw;2 6dMoon's .di/lqc;z(z m 26jgxw gravity is one sixth of Earth's. Compare the masses of the objects.

  Sue and Sean are having a tu3v vavfa,:2gg g-of-war by pulling on opposite ends of a 5.0-kg rope. Sue pulls with a 15-N fvag2v: 3 vgf,aorce. What is Sean'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 fni6 p.c+ruu0 force F acts on the stackucif 0n+. upr6, and 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 willw),ppts s q8)q the scale be reading when the elevator is accelerating qq)8 s)tpw ps,downward at $4.00 \; m/s^2$?

  A person on a scale rides in an elevator. If the mass of the person ik g-yoian*n,9, ) wqpn5koueny7l 9v+ s 60.0 kg and t)o v*9u9n,,g-neyn+iy kl7 aqwkopn 5he 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 ,s(kvfcmu(9 : ebpst)98bs*ycb- hwgthe person is 60.0 kg and the elevator ss8v)y-kgh,mw (cec*p9 b : tb(sb9fuaccelerates 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 magnitude of 8 6t; ijro62qkyrbgv)).0 N and is directed due tgyo j k6i;)br)r2v6qnorth. 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. It is held in placvz7 v*)osc x2+zlb8kde by metal brackets that can exert a maximum horizontal force of 9z +szovb)kx28c 7 dv*l000 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 flatbed of a truck. I:j;rmrre7gxrf,25 ,1iofxr lt is held in place by metal brackets that can exert a m : mgr ,2x5fior1r7r jlxr;f,eaximum 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 kg and m = 0.40 kg, whaz8 g7;;lwjshm (2i 0zy(nlo +6zzi afft is the magnitude of the acceleration of the system? (;s2lzfi6w;8ho z7(nzgfmz j+ ia 0yl(Ignore friction and the mass of the pulley.)

  In the Atwood machine sh0ml iq1)h(l ou5v4lbzown in Fig. 4-1, if M = 0.60 kg and m = 0.40 kg, what is the tension in the string? (Ignore fulvzi lm0)o (bq l14h5riction and the mass of the pulley.)

  A student pulls a box of books on a smooth ox. 1pcol nso4gfw c)zb 2.p5-t,:toohorizontal floor with a force of 100 N in a directi 5tz:).nop c14lox tbgf,sow -o.poc2 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 fo4o1*xt ( 1bzmlpb3 hjwrce 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, what is the normal1l(ph1 b4tmz j*wxob 3 force on the box?

  A traffic light of weight 100 N is supported by two ropes as sx;i2wzyj oq11x y e,qcpx+a 02hown in Fig. 4-2. What are the tensions in the ropayw q1e+ix1,;0zycq 2xoxp2 jes?

  In Fig. 4-2, if the tensmfgv;ldsu ;g2g +5 1lmsq9y c8ions in the ropes are 50 N, what is the mass of the trafg1vcllqu;2s fggm 85myd; +9sfic light?

  Two boxes of masses m and 2m are in contact with each other on a frictic z/a4*khe d v:p:rz+;hbfl/e n5p q.konless surface. (See Fig. 4-3.) What is the ac /+ra e.k4eh:cvlnzk;pzd q:h* /b5fp celeration of the more massive box?

  Two boxes of masses m and 2m are in contvn v. 0um.qs)(hyr9hgr-hv3 cact with each other on a frictionless surface. - (0 myh.gv3 hc)r9rvqhsun .v (See Fig. 4-3.) What is the net force on the more massive box?

  Two boxes of masses m y ,ctah x0ee+f+hkw+;/8hifyand 2m are connected by a rope. (See Fig. 4-4.) If the forwar f +iet/yhhc+e,x wfah08; k+yd force on the more massive box is F, what is the tension in the connecting rope?

  Two boxes of masses m and 2m are connected by a rope. (See 5rznmf)v d7r9q1 yim*Fig. 4-4.) If the forward force on the more massive box is F, what is the acceleration of t dnmf* rz) y5qiv9r7m1he less massive box?

Two boxes are connected by a cord running over a pullr a+l0j z6-gfyey as shown in Fig. 4-5. Box I of masrg+0 6-f yjlazs
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 kinetivd-7xzq cd-u( c 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 horizontal force is applied to the box?7zdqdcx-( v -u

  The coefficients of static and kinetic frictions for plastic on wood are 0.50 aessh v0i)2iru (wtqw8-m(2+obzhw 8 t nd wuv8sht( i)(r+-2smhetbi0 2 wozqw80.40,
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 in the +x direction. ozn.g*zs tgn(/,hl;x,hlfw wp/*x /xIt slows and comes to a stop w lxwp sxn;go /,lzt*g/.zx,f* hn h(/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 horizontalhzujz( jj r d0ns:.wj-n() 4sn surface is pulled by a 5.0-N force. A 3.0-N friction force retards the motion. W:zdnnn0(.jujwjsj h4zrs-) ( hat is the acceleration of the object?

  A horizontal force of 5.0 N accelerates a 4.0-kg mass, from s w6o.wrfykk/ tfc2u .c3*z9h9;q cibrest, 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 gfei-5zg3gh6alk ; (oyiven an initial speed of 10 m/s. It slides 50 m on the ice before it st ky3oge6f-ah(z;lgi 5 ops. What is the coefficient of kinetic friction between the puck and the ice?

  During the investigation of a traffic accident, police find skid marks 90.0of h ddfo 6m*iko( yvfbyq9m po87995) m long. They determine the coefficient of friction between the c6mhiy oo 9yvdf9b)k o m58f9*p o7d(fqar'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-pa7k 6w3 .-f0y yijori6.) The surface between the more massive box and the horizontal yp ja0-iokyfi6 rw.37 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 static friction force on the less massive box?

  Two boxes of masses m andpbi-u yc4m7:w 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 niyc74- pbw:muot slide on the more massive box, what is the coefficient of static friction between the boxes?

  An object is on a frict9l7fiw 9wc; hob 9ctrfqn96e;ionless inclined plane. The plane is inclined at an angle9h; fceifoc; lb9rn6t w9q 9w7 of $30^{\circ}$ with the horizontal. What is the object's acceleration?

  A 10-kg mass slides down a flat hill that makes z sln1my rj574/ fla by(4btk9an 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 l5 vmj59be:v;j p7jqlwith 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 smoorv+vn;tgvnt0j(fw)l 3r 4td . th 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 b 0bza2y. eob,ova pod:h03:cconstant velocity of 6.p3 d oo y.v:b2 ,hb0:aeac0ozb0 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 a rnh mdg3u/+ ;tsh7r v1rough $37^{\circ}$ inclined plane where the coefficient of kinetic friction is 0.20. What is the acceleration of the object?

  An object with a mass m slidek.) g iwg*hm2uju 2a*f:iew)ds 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 500 N alonnwhl)x:d w6pi3e ;4wa g a rough surface. The cable attached to the log makes an angle of xhniaweww:3;6 dl) 4p$30.0^{\circ}$ 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 tilte8ku ;- rcui j. ,-b4zbs(icyond at an angle jk -yncu c,ir8u-;s4b i.zb(oof $33.5^{\circ}$ 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 1a--mmbc;v(6 rxf x 95coyzxk inclined plane. The angle of incline is gradually increased until the object begins to slide. The angle at which this occurs is q. What ixv ayxmcb;1ck(6 orf--9m 5xzs the coefficient of static friction between the object and the plane?