A15-kg sled is being pulled along the horizontal snow-covered ground by a horizontal force of 23 n. starting from rest, the sled attains a speed of 1.8 m/s in 8.5 m. find the coefficient of kinetic friction between the runners of the sled and the snow.

The experiment done in lab is repeated, using a ball that has unknown mass m. you plot your data in the form of f 2 versus m/l, with f in rev/s, m in kg, and l in m. your data falls close to a straight line that has slope 3.19 m/(kg · s2). use g = 9.80 m/s2 and calculate the mass m of the ball.