Final answer:
The x-coordinate of the cart is defined as the position or distance from a reference point in the given experiment. Time is the independent variable often plotted on the x-axis of a velocity-time graph, with velocity as the dependent variable. To measure cart velocities in an experiment, use motion sensors or time-stamped photographs and account for possible measurement errors.
Step-by-step explanation:
In the experiment described, the x-coordinate of the cart is defined as the position of the cart along the straight horizontal track. This position, or x-coordinate, relates primarily to the distance the cart has moved from a specific reference point. When plotting a velocity-time graph, typically, time is placed on the x-axis as the independent variable, and velocity is placed on the y-axis as the dependent variable, indicating how velocity changes over time. The four variables found in the kinematic equations, which are important for understanding the movement of carts in the experiment, include acceleration, displacement, time, and velocity.
An experimental procedure to determine the velocities of the carts before and after the collision would involve using motion sensors or photographing the track with timing markers. Measurements would be taken for the time intervals and positions to calculate velocities. Possible sources of error might include measurement inaccuracies or air resistance, although it's stated that the carts have negligible friction.