Question

an object of mass m is released from rest from the top of a smooth inclined plane of height h. it's speed at the bottom of the plane is proportional to
(a) m°
( b) m
(c) m2
(d)m^-1

Answer 1

Using work energy theorem

1212mv2=mgh−(μmgcosθ)(hsinθ)mv2=mgh−(μmgcos⁡θ)(hsin⁡θ)

where hsinθhsin⁡θ=length of the incline.

'h' hight of incline and ′θ′′θ′ angle of incline.

v=2gh−2μghcotθ−−−−−−−−−−−−−√v=2gh−2μghcot⁡θ

vαm0vαm0

Hence a is the correct answer.