Question

A block of mass `2 kg` si kept at rest at `x = 0`, on a rough horizontal surface with coefficient of a rough horizontal surface with coefficient of friction `0.2`. A position dependent horizontal force given by `F = x^(2)+2x+5` (where x is in meter and `F` is in Newton), starts acting on the block at `x = 0`. The kenetic energy of block at `x = 3` is :
A. `21 J`
B. `33J`
C. `45 J`
D. `12J`

Answer 1

Correct Answer - A
A block ………..
`W_(F)+W_(t)=Delta k`
`int_(0)^(3)(x^(2)2x+5)dx+(-mu mgxx3) = K - 0`
`k = 33 - 12 = 21 J`