J & K CET Medical
J & K - CET Medical Solved Paper-2001
question_answer
A block slides with a velocity of 10 m/s on a rough horizontal surface. It comes to rest after covering a distance of 50 m. If g is \[10\text{ }m/{{s}^{2}},\] then the coefficient of dynamic friction between the block and surface is:
A) 1
B) 10
C) 2
D) 0.1
Correct Answer:
D
Solution :
From equation of motion, we have \[{{v}^{2}}={{u}^{2}}+2as\] where v is final velocity, u the initial velocity, a the acceleration and s the displacement. Given,\[v=0\](block stops),\[u=10\text{ }m/s,\] \[s=50\text{ }m\] \[\therefore \] \[0-{{10}^{2}}=2\times a\times 50\] \[\Rightarrow \] \[a=-1\text{ }m/{{s}^{2}}=ug\] \[\Rightarrow \] \[\mu =\frac{1}{10}=0.1\]