Question

The speed of a falling object increases at a constant rate as time increases since the object was dropped. Which graph could represent the relationship between t, time in seconds, and s, speed in meters per second?

A graph shows dropping time (seconds) labeled 1 to 10 on the horizontal axis and object speed (meters per second) on the vertical axis. A line increases from 0 to 10 seconds.
A graph shows dropping time (seconds) labeled 1 to 10 on the horizontal axis and object speed (meters per second) on the vertical axis. A line decreases from 0 to 4 seconds.
A graph shows dropping time (seconds) labeled 1 to 10 on the horizontal axis and object speed (meters per second) on the vertical axis. A line increases from 0 to 4.5 seconds.
A graph shows dropping time (seconds) labeled 1 to 10 on the horizontal axis and object speed (meters per second) on the vertical axis. A line decreases from 1 to 9 seconds.

Answer 1

The first graph.

Because speed increases at a constant rate, s vs. t is a straight line with positive slope — the first graph shows a line increasing from t = 0 to t = 10, which matches.