Asked by LG
                A 0.170 kg hockey puck is initially moving at 21.2 m/s [W] along the ice. The coefficient
of kinetic friction for the puck and the ice is 0.005.
(a) What is the speed of the puck after traveling 58.5 m?
my solution:
Fnet=Fk
ma=μk.Fn
ma=μk.mg
a=(0.05)(0.170kg)(9.8m/s2)0.170kg
=0.049m/s2
Vf2=Vi2+2ad
=(21.2)2−(0.049)(58.5)−−−−−−−−−−−−−−−−−−√
=21.13m/s
(b) After being played on for a while, the ice becomes rougher and the coefficient of
kinetic friction increases to 0.047. How far will the puck travel if its initial and final
speeds are the same as before?
my solution:
Fnet=Fk
ma=μk.Fn
ma=μk.mg
a=(0.047)(0.170kg)(9.8m/s2)0.170kg
=0.04606m/s2
.. then i don't know what's next..
i got part a right but i'm having trouble with part b... please help.
            
            
        of kinetic friction for the puck and the ice is 0.005.
(a) What is the speed of the puck after traveling 58.5 m?
my solution:
Fnet=Fk
ma=μk.Fn
ma=μk.mg
a=(0.05)(0.170kg)(9.8m/s2)0.170kg
=0.049m/s2
Vf2=Vi2+2ad
=(21.2)2−(0.049)(58.5)−−−−−−−−−−−−−−−−−−√
=21.13m/s
(b) After being played on for a while, the ice becomes rougher and the coefficient of
kinetic friction increases to 0.047. How far will the puck travel if its initial and final
speeds are the same as before?
my solution:
Fnet=Fk
ma=μk.Fn
ma=μk.mg
a=(0.047)(0.170kg)(9.8m/s2)0.170kg
=0.04606m/s2
.. then i don't know what's next..
i got part a right but i'm having trouble with part b... please help.
Answers
                    Answered by
            Elena
            
    ma=F(fr) =μN=μmg
a= μg.
s=(v₀²-v²)/2a=
=(v₀²-v²)/2μg =>
v=sqrt{v₀²-2μgs}=
=sqrt{21.2²-2•0.005•9.8•58.5} =
=21.06 m/s.
For the 2nd case:
s=(v₀²-v²)/2μ₁g=
=(21.2²-21.06²)/2•0.047•9.8=6.42 m
    
a= μg.
s=(v₀²-v²)/2a=
=(v₀²-v²)/2μg =>
v=sqrt{v₀²-2μgs}=
=sqrt{21.2²-2•0.005•9.8•58.5} =
=21.06 m/s.
For the 2nd case:
s=(v₀²-v²)/2μ₁g=
=(21.2²-21.06²)/2•0.047•9.8=6.42 m
                    Answered by
            LG
            
    Thank you
    
                    Answered by
            Rafae Adil
            
    Bruuh i dont understand
    
                    Answered by
            Rafae Adil
            
    I, Rafae Adil, am an idiot
    
                    Answered by
            Adrian
            
    You bafoon, you used 0.5 as mu in ur calculations but its really 0.005 in the question
    
                    Answered by
            Vladimir Putin
            
    you dumbo, you didn't put a slash and it looks like you multiply
    
                    Answered by
            Leila
            
    How did you get F net is equal to F k
    
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