A block of mass 2 kg is sliding on a rough horizontal surface. The velocity-time graph of the block's motion is a straight line. The graph intersects the velocity axis at 12 m s ⁻¹ and the time axis at 4 s . The value of the coefficient of kinetic friction between the block and the surface is: (Take g = 10 m s ⁻² )

Step-by-step solution

From the velocity-time graph, the initial velocity is u = 12 m s ⁻¹ and the final velocity is v = 0 at t = 4 s . The magnitude of deceleration is given by the slope of the velocity-time graph: a = 12 - 0 4 = 3 m s ⁻² The only horizontal force acting on the block is the kinetic friction, which provides the deceleration. f_k = m a _k m g = m a _k = a g Substituting the values: _k = 3 10 = 0.3 Answer: 0.3