Question

Statics

1. The block shown in the figure has a mass of 612 Kg. The static coefficient of friction between the block and the supporting surface is 0.33 while the kinetic coefficient of friction is 0.26. Ignore the size of the block. Force Pis parallel to the incline while the 1000N force is vertical. a) If P= 2000 N, the shown block is (circle the correct answer) (5 points) a) in equilibrium b) moving up the incline c) is about to move up the incline (impending motion) d) moving down the incline e) is about to move down the incline (impending motion) b) If P = 4000 N, the shown block is (circle the correct answer) (5 points) a) in equilibrium b) moving up the incline c) is about to move up the incline (impending motion) d) moving down the incline e) is about to move down the incline (impending motion) 1000 N 60 degrees

Answer 1

Solutions Givena Mars of block = M=612 kg ". kleight (W} 612x9.81N - 6003.72 N. Me = 0.33 RR= 0.26. 1100ph 10000 Bin 60=866.025N 300 -8 6N 6003.72xCosta WCOSCO W ooo ckco droon W singo' =6003.72xSingo 5199.374N 500 NS It P=2000N Total of weight (W)=6003-72N and plus loooN applies down. If weresolve these into components along incline soface & perpendi- -cular to incline surface Force along incleine = (6003. 72. +1000) singo Force glar = 6065.4 N to incline (6003.72 +1000) x Cos Gol = 3501.8GN. 850 1.860 Normal force on blocken) = 3501-86 N.

static friction Efs): - fs= M N = 0.33 x 3501.86 ds = 155.6138 N. Kinematic triction (f) fk = MAN= 0.26x3501-86 ifk=910.4836 N. P=2000N Now P=2000N fe 6065.4 N 2000 ffs = 2000+ 1155.6138 =3155-6138 N 3155-61380 6065.UN 6065-UN > 3155.6138 N i Block will more down the inclined plane. Because it is moving fx will be applied. 2000N fK 2910.983) 6065.UN. 2000+910.4836 (6065-4 2910.4836N 606562- Therefore block moves down the inclined plane 5315409 with resultan force of 3154.90

in on block along direction parallel inclination down. Answer: option d' If P24000N; 400ON fs 6065.40 4000 + fs = 4orot 1155.6138 5155-6138N 5155.61389 6665.40 5155.6138 C60654N. . Block mores down the Inclined plane. you tk 6065.GN Hooot&k= 4000+ 910.4836 = 491048 36 6065-4-4910.4836 1154-9164N As it is moving, tk will apply .. Block moves down the inclined plane with resultant force of 1154.9164 N on block in the direction of down the plance Answer option ď.