Question :-
How much time would it take for a 0.17 kg ice hockey puck to decrease its speed by 9.0 m/s if the coefficient of kinetic friction between the ice and the puck is 0.05
Given:-
- mass = 0.17 kg
- change in speed= 9 m/s
- coefficient of kinetic friction = 0.05
To Find :-
Time taken to decrease the speed
Answer:-
Equation :-
[tex]f {\tiny{k} }= u {\tiny{k}}.f \tiny{N}[/tex]
[tex]f {\tiny{N} }= mg = 0.17 \times 10 \\f {\tiny{N} }= 1.7 {N}[/tex]
[tex]u{ \tiny{N}} = 0.05[/tex]
[tex]mg = f {\tiny{k} }= u {\tiny{k}}.f {\tiny{N}} \\ 0.17a = 0.05 \times 1.7 \\ a = 0.05 \times \frac{ \cancel{1.7} {}^{ \: \: 10} }{ \cancel{0.17}} \\ a = 0.5m {s}^{ - 2} [/tex]
change in speed = 9 ms-1 (Given)
[tex]change \: in \: speed = at \\ 9 = 0.5 \times t \\ \frac{9 \times 10}{5} = t \\ \frac{9 \times \cancel{10} {}^{ \: \: 2} }{ \cancel{5}} = t \\ 18 \: sec = t \: [/tex]
