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A 2 kg block slides on a horizontal floor with a speed of 4 m/s. It strikes an uncompressed spring, and compresses it till the block is motionless. The kinetic friction force is 15 N and spring constant is 10,000 N/m. The spring compresses by : |
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Answer» 2.5 cm `:.1/2mv^2=1/2kx^2+F_kxxx` `1/2xx2xx(4)^2=1/2xx10,000x^2+15 x` `32=10,000x^2+30 x` `:.10,000x^2+30 x-32=0` or `x=(-30pmsqrt(900+4xx10,000xx32))/(20,000)` =`(-30pm1132)/(20,000)=(1102)/(20,000)xx100 cm` implies 5.5 cm |
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