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 10000 N/m. The spring is compressed by (in cm):

Explanation

`KE = 1/2(mv^(2)) = W_("friction") + 1/2Kx^(2)`
`1/2 xx 2 xx 4^(2) = 15x + 1/2 xx 10000 xx x^(2)`
`Rightarrow 5000x^(2) + 15x - 16 = 0`
`Rightarrow x = 0.055m or x = 5.5 cm`.