Chapter 5, Problem 5.90AP

A student is asked to measure the acceleration of a glider on a frictionless, inclined plane, using an air track, a stopwatch, and a meterstick. The top of the track is measured to be 1.774 cm higher than the bottom of the track, and the length of the track is d = 127.1 cm. The cart is released from rest at the top of the incline, taken as x = 0, and its position × along the incline is measured as a function of time. For x values of 10.0 cm, 20.0 cm, 35.0 cm, 50.0 cm, 75.0 cm, and 100 cm, the measured times at which these positions are reached (averaged over five runs) are 1.02 s, 1.53 s, 2.01 s, 2.64 s, 3.30 s, and 3.75 s, respectively, (a) Construct a graph of x versus t², with a best-fit straight line to describe the data, (b) Determine the acceleration of the cart from the slope of this graph, (c) Explain how your answer to part (b) compares with the theoretical value you calculate using a = g sin θ as derived in Example 5.6.