If the speed decreases to 40 kmb in 5sdetermine the coefficient ofkinetic

If the speed decreases to 40 kmb in 5sdetermine the

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Ifthespeed decreases to 40km/bin 5s,determine the coefficientofkinetic friction between the tires and the road.Prob.IS-13Prnb.IS-lS
II~15-18. The motor exerts a forcePon the40-kgcrate asshown in the graph. Determine the speed of the crate whent=3 s and whent=6 s.Whent=0, the crate is movingdownward at10m/s.250CHAPTER15KINETICSOFAPARTICLE:IMPULSEANDMOMENTUM*15-16. The choice of a seating material for movingvehicles depends upon its ability to resist shock andvibration. From the data shown in the graphs, determine theimpulses createdbya falling weight onto a sample ofurethane foam and CONFOR foam.F(N)1.2+------A0.8+-----~Io.s0.40.32"'---f-+--+---+--~f--t(ms)144107Prob.15-16~17.The towingforceactingon the 400-kgsafevariesasshown on the graph. Determine its speed, starting from rest,whent-:8 s.How far has it traveled during this time?F(N)750 -------,600-----,("'------SL--LS--t(s)Prob.15-17'--~----l6~---t(s)Prob.15-1815-19. The 30-kgslider block ismovingto the leftwithaspeed of5mjs when itisacted upon by the forces F1and F2.Itthese loadings vary in the manner shown on the graph,determine the speed of the block atI=6s.Neglect frictionand the mass ofthe pulleys and cords.[email protected]F, @~!:F,F(N)40F,3020toF,t(s)0246Prob.15-19...
15.2PRINCIPLE OF LINEAR IMPULSE AND MOMENTUM FOR A SYSTEM OF PARTICLES*15-20. The 200-lb cabinet is subjected to the forceF=20(t+1)lbwheretisin seconds.Ifthe cabinet isinitiallymoving to the left with a velocity of 20 ft/s, determine itsspeed whenl=5s.Neglect the size of the rollers.=F=Prob.15-2015-21.Ifittakes 35sfor the 50-Mg tugboat to increase itsspeed uniformly to 25 km/h, starting from rest, determinethe force of the rope on the tugboat. The propeller providesthe propulsion force F which gives the tugboat forwardmotion, whereas the barge moves freely. Also, determineFacting on the tugboat. The barge has a mass of75Mg.Prob.15-2115-22. The thrust on the 4-Mg rocket sled isshown in thegraph. Determine the sleds maximum velocity and thedistance the sled travels whent=35s.Neglect friction.T(kN)25120+------:=.,L------2-1-5--~3'-:5----t(s)Prob.15-2215-23. The motor pulls on the cable atAwith a forceF=(30+tz)lb, wheretis in seconds.Ifthe 34-lb crate isoriginallyonthe ground att=0,determine itsspeedinl=4s.Neglect the mass of the cable and pulleys.Hint:First findthe time needed to begin liftingthe crate.Prob.15-23*15-24. The motor pulls on the cable atAwith a forceF=(e21)lb,where tis inseconds.Ifthe34-lbcrate isoriginallyat rest on the ground atl=0,determine the crate's velocitywhent=2s.Neglect the massofthe cable and pulleys.Hint:Firstfind the time needed to begin liftingthe crate.Prob.15-24
15-27. The20-kgcrate islifted byalorce ofF=(100+51')N,wheretisin seconds. Determine the speed of the crate whent=3S,starting from rest.*15-28. The 20-kg crate is lifted by a force ofF=(100+51') N,whereIisinseconds. Determine how highthe crate has moved upward whent=3s,starting from rest.

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