A2L Item 037

• Description: Identify correct force graph for block dropped on a spring.
• Goal: Translate a verbal description of physical motion to graph of force.
• Source: UMPERG
• Keywords: Dynamics, Forces, Graphing, Mechanics, Springs

---

The question for students:

A block is dropped onto a vertical spring. Which net force vs. time graph best represents the net force on the block as a function of time? Consider only the motion of the block from the time it is dropped until it first comes to rest.

---

Commentary for teachers:

Answer

(4); Some students may select (5) confusing the equilibrium point with the point where the block comes to rest. Students selecting (2) are ignoring gravity after the block hits the spring.

---