Homework Questions? Ask a Tutor for Answers ASAP
Hi, answers to your questions are shown below in bold font.Equation for speed as a function of time for constant acceleration is:v = u + at where v is the final speed, u is the initial speed, a is the acceleration, and t is the time elapsed. This gives a = (v - u)/tIn this case, v = 6 m/s, u = 12 m/s, t = 5s.Thus a = (6 - 12) / 5 = -1.2 m/s^2Average acceleration = - 1.2 m/s^2(The negative sign means it is decelerating).From laws of motion we have F = ma, where F is the force, m is the mass, and a is the acceleration. So we have:F = -1.2m with m being the mass of the puck. The force is negative because it acts in a direction opposite to the motion of the puck.The magnitude of the force is the force of friction. The friction force Q is given as:Q = cmg, where c is coeff of friction, m is the mass of the puck, and g is the gravitational acceleration (9.8 m/s^2). Thus we have:1.2m = cmgwhich gives c = 1.2/g = 1.2/9.8 = 0.1224Thus, coeff of kinetic friction is 0.1224.Distance traveled d is given by:d = ut + 0.5at^2Again, u = 12 m/s, a = -1.2 m/s^2, t = 5s. This gives d = 12x5 - 0.5x1.2x25 = 45 mDistance traveled by puck = 45 m
That was quick! i now know where i went wrong with this problem.