Question

A block with initial velocity of 3 m/s slides 9 m across a rough horizontal surface before coming to rest. What is the coefficient of kinetic friction?

Answer 1

`k~=0,051`

Explanation:

`"if object stops, velocity of object is zero."`
`v_l: " last velocity of object"`
`v_i:" initial velocity of object"`
`a:" acceleration of object"`
`x:" displacement of object"`
`F_f:" friction force acting contacting surface"`
`k:" coefficient of kinetic friction"`
`v_l^2=v_i^2-2.a.x`
`0=3^2-2*a*9`
`cancel(9)=2*a*cancel(9)`
`a=1/2 m/s^2`
`F_f=m*a`
`k*cancel(m)*g=cancel(m)*a`
`k=a/g`
`k=(0,5)/(9,81)`
`k~=0,051`