---
title: "A student drops two spheres of the same diameter, one made of solid steel and one made of hollow plastic, from the top of a very tall building at the same time. The student uses a motion sensor to record the velocity of each sphere as it falls through the air. The student observes that the steel sphere hits the ground before the plastic sphere. Which of the following is a correct explanation for this observation?"
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url: "https://nerd-notes.com/ubq/110077/"
date_modified: "2026-03-26T11:47:24+00:00"
---

# A student drops two spheres of the same diameter, one made of solid steel and one made of hollow plastic, from the top of a very tall building at the same time. The student uses a motion sensor to record the velocity of each sphere as it falls through the air. The student observes that the steel sphere hits the ground before the plastic sphere. Which of the following is a correct explanation for this observation?

A student drops two spheres of the same diameter, one made of solid steel and one made of hollow plastic, from the top of a very tall building at the same time. The student uses a motion sensor to record the velocity of each sphere as it falls through the air. The student observes that the steel sphere hits the ground before the plastic sphere. Which of the following is a correct explanation for this observation?

- **A.** The steel sphere hits the ground first because, at any given speed, its acceleration is greater and remains closer to \(g\) for a longer period of time.
- **B.** The spheres should have hit the ground at the same time because the acceleration due to gravity is \(9.8 \text{ m/s}^2\) for all objects regardless of mass.
- **C.** The steel sphere hits the ground first because it has more mass, and objects with more mass are naturally less affected by the force of gravity.
- **D.** The plastic sphere hits the ground last because its lower mass causes it to have a larger initial acceleration, which causes it to reach its terminal velocity too quickly.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/110077/*