Question

question 2 (3 points) (01.09 mc) position vs. time... which statement accurately describes the motion of the object in the graph above? a it is at rest for 3 seconds before moving at constant speed for 10 seconds. b it is at rest for 3 seconds before moving at constant speed for 4 seconds. c it is moving from 0 cm to 5 cm at constant speed of 7 cm/s. d it is moving from 0 cm to 3 cm at a constant speed of 3 cm/s.

Explanation:

1. Analyze option a: The graph shows the object is at rest from 3s to 6s (3 seconds), then moves. The total time of motion after rest is from 6s to 10s, which is 4s, not 10s. So a is wrong.
2. Analyze option b: The object is at rest between 3s and 6s (3 seconds). Then from 6s to 10s, it moves at constant speed (since the graph is a straight line), and 10 - 6 = 4 seconds. This matches.
3. Analyze option c: From 0cm to 3cm (not 5cm) initially, and speed calculation: speed = distance/time. From 0 to 3cm, time is 3s, speed = 3/3 = 1 cm/s, not 7 cm/s. So c is wrong.
4. Analyze option d: From 0cm to 3cm, time is 3s, speed = 3/3 = 1 cm/s, not 3 cm/s. So d is wrong.

Answer:

b. It is at rest for 3 seconds before moving at constant speed for 4 seconds.