A block of wood of 1 kg resting on an inclined plane of angle `30^(@)`, just starts moving down. If the coefficient of friction is 0.2, then find its velocity (in `ms^(-1)`) after 5 s (take , `g=10ms^(-2)`)

Explanation

Acceleration of block down the plane is given by

For the motion of body along the incline,
`a=(mg sin theta-mu mg cos theta)/(m) ( "as" ,R=mg cos theta "and " f_(s)=muR)`
`=10xx sin 30^(@)-0.2xx10 cos 30^(@)`
`=10xx(1)/(2)-2xx(sqrt3)/(2)=3.278 ms^(-2)`
From equation of motion, v=u-at
Velocity after 5 s
`v=0+3.278xx5=16.35 ms^(-1)`