Original Project
Force and Motion
If a force acts on an object in the direction opposite to the direction of the object’s motion, the object’s…
Item FM055004: The speed of a sailboat will continue to decrease the entire time the force of the water slowing it down is greater than the force of the wind pushing it forward.
In the drawing below, the arrows labeled WIND and WATER represent forces acting on a sailboat. The directions of the arrows represent the directions of the forces, and the lengths of the arrows represent the strengths of the forces. The force of the water on the sailboat is stronger than the force of the wind on the sailboat the entire time.
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Which statement describes the sailboat’s motion while these forces are acting? Assume that the sailboat does not stop or turn around.
- The sailboat’s speed will decrease the entire time.
- The sailboat’s speed will stay the same the entire time.
- The sailboat’s speed will decrease for a while and then stay the same.
- The sailboat’s speed will stay the same for a while and then decrease.
- Distribution of Responses
- Students Responding Correctly
| Group | Correct | Total | Percent |
|---|---|---|---|
| Overall | 1213 | 3511 | 35% |
| Grades | |||
| 6–8 | 742 | 2223 | 33% |
| 9–12 | 469 | 1279 | 37% |
| Gender | |||
| Male | 652 | 1670 | 39% |
| Female | 534 | 1771 | 30% |
| Primary Language | |||
| English | 1114 | 3163 | 35% |
| Other | 73 | 277 | 26% |
- Disciplinary Core Ideas
- PS2.A The motion of an object is determined by the sum of the forces acting on it; if the total force on the object is not zero, its motion will change. The greater the mass of the object, the greater the force needed to achieve the same change in motion. For any given object, a larger force causes a larger change in motion.
PS2.A Newton's second law accurately predicts changes in the motion of macroscopic objects.