A body of mass 100 g moving on a test track has final KE of 50 J after traveling a distance of 10 cm. Assuming `90%` loss of energy due to friction, find the intial speed of the body

Explanation

Hint : `(1)/(2)mv^(2)=50J`
If initial KE is `K_(i)` then `K_(l)xx(10)/(100)=50` Find `K_(i)`
`K_(i)=(1)/(2)m u^(2)" "m=(100)/(1000)kg`.
Find u.
`(1)/(2)mv^(2)=50J`
`"Initial KE"=K_(i)`
`K_(i)xx(10)/(100)=50`
`K_(i)=500J`
`(1)/(2)m u^(2)=500`
`u=sqrt((2xx500)/((100)/(1000)))=100ms^(-1)`