Answer:
Explanation:
Given
mass of box[tex]=2.5 kg[/tex]
speed [tex]v=1.2 m/s[/tex]
compression in the spring [tex]x=2 cm[/tex]
Total Initial energy [tex]K.E.=\frac{mv^2}{2}[/tex]
[tex]K.E.=\frac{2.5\times 1.2^2}{2}=1.8 J[/tex]
Thermal energy generated is [tex]E=0.5 J[/tex]
this thermal energy is produced by friction force
Work done by Friction Force is [tex]W=f_r\cdot s[/tex]
[tex]f_r=\mu _k\times N[/tex]
where [tex]\mu_k =coefficient\ of\ kinetic\ friction[/tex]
[tex]N=mg[/tex]
[tex]f_r=\mu _kmg[/tex]
[tex]0.5=\mu _k\times 2.5\times 10\times 0.02[/tex]
[tex]0.5=\mu _k\cdot 0.5[/tex]
[tex]\mu _k=1[/tex]
[tex]\mu _k=1[/tex] contradicts the fact that friction is present because [tex]\mu _k=1[/tex] shows there is no friction so either surface is friction less or compression in the system should be more than 2 cm
