---
title: "A ship travels horizontally to the right across calm water at a constant velocity \\(v_{\\text{ship}}\\) relative to a dock. A deckhand standing on the deck tosses a small ball vertically upward with an initial speed \\(v_0\\) relative to the ship, catching it at the same height from which it was released. A runner standing stationary on the dock watches the entire motion of the ball. Which of the following claims correctly compares the physical quantities measured by the deckhand on the ship and the runner on the dock?"
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url: "https://nerd-notes.com/ubq/119040/"
date_modified: "2026-08-18T04:46:59+00:00"
---

# A ship travels horizontally to the right across calm water at a constant velocity \(v_{\text{ship}}\) relative to a dock. A deckhand standing on the deck tosses a small ball vertically upward with an initial speed \(v_0\) relative to the ship, catching it at the same height from which it was released. A runner standing stationary on the dock watches the entire motion of the ball. Which of the following claims correctly compares the physical quantities measured by the deckhand on the ship and the runner on the dock?

A ship travels horizontally to the right across calm water at a constant velocity \(v_{\text{ship}}\) relative to a dock. A deckhand standing on the deck tosses a small ball vertically upward with an initial speed \(v_0\) relative to the ship, catching it at the same height from which it was released. A runner standing stationary on the dock watches the entire motion of the ball. Which of the following claims correctly compares the physical quantities measured by the deckhand on the ship and the runner on the dock?

- **A.** The runner measures a greater acceleration than the deckhand because the ball has both horizontal and vertical components of acceleration relative to the dock.
- **B.** The runner measures a greater time of flight than the deckhand because the ball travels along a longer parabolic path relative to the dock.
- **C.** Both observers measure the same time of flight and the same acceleration because time intervals and vertical acceleration are invariant between inertial reference frames.
- **D.** Both observers measure the same horizontal velocity component because the ball was launched strictly vertically relative to its starting surface.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/119040/*