A body is projected along a rough horizontal surface with a velocity 6

1.	A body is projected along a rough horizontal surface with a velocity 6m/s. If the body comes to rest after travelling 9m then coefficient of sliding friction is
Answer» Answer: Coefficient of sliding friction is 0.204 Explanation: It is GIVEN that, Initial velocity of the body, u = 6 m/s Final velocity, v = 0 (as it comes to rest) Distance, d = 9 m $\mu_s$ We need to FIND the coefficient of sliding friction. Let it is equal to . Frictional force is given by : $F=\mu_s\times N$ $F=\mu_s\times mg$ Also, $ma=\mu_s\times mg$ $\mu_s=\dfrac{a}{g}$ ...............(1) Acceleration, a can be CALCULATED using THIRD equation of motion as : $a=\dfrac{v^2-u^2}{2s}$ $a=\dfrac{-(6\ m/s)^2}{2\times 9\ m}$ $a=-2\ m/s^2$ The minus sign shows that the force is acting in opposite direction of frictional force. Equation (1) BECOMES, $\mu_s=\dfrac{2}{9.8}$ $\mu_s=0.204$ So, the coefficient of sliding friction is 0.204. Hence, this is the required solution.