shows an accelerometer, a device for

measuring the horizontal accel- eration of cars and airplanes. A

ball is free to roll on a parabolic track described by the equation y = x2 , where both x and y are

in meters. A scale along the bot- tom is used to measure the ball's

horizontal position x. a. Find an expression that allows you to use a measured position x (in m) to compute the acceleration ax (in m/s2

). (For example,

ax = 3x is a possible expression.) b. What is the acceleration if x = 20 cm?