Mission VP8 Velocity and Acceleration of a Projectile
Which of the following statements are true of a projectile's acceleration? List all that apply ...
A projectile is an object for which the only force acting upon it is gravity. The force of air resistance is negligibly small or nonexistent for a projectile.
Most questions in Minds On Physics require a minds-on approach. A student must think about what they know and how that knowledge can be logically applied to a given question. In the process of scanning one's knowledge base, a student must be aware of misconceptions, fallacies and errors of reasoning.
This question is a perfect example of the need for a minds-on approach. Think about what you know about a projectile's acceleration and apply it to this question. Use your textbook, your class notes, any worksheets you have completed, and online links (see the Hot Link section). And perhaps best of all, take the 2-3 minutes required to read and study the Don't Be Fooled section.
This entire mission contains questions that focus a student's attention on the acceleration and the velocity of a projectile. Many questions (such as this one) contain choices which target common student misconceptions. While the choices may sound good, they're far from the truth. Contrast the following misconceptions and the accurate physics concepts.
Misconception: The acceleration of a projectile is 0 m/s/s at the peak of the projectile's trajectory.
Correct Concept: The vertical component of the velocity of a projectile is 0 m/s at the peak of its trajectory.
Misconception: The acceleration is directed upward as the projectile rises toward its peak.
Correct Concept: The vertical component of the velocity of a projectile is directed upward as the projectile rises toward its peak.
Misconception: The acceleration of a projectile decreases as the projectile rises upward toward its peak.
Correct Concept: The vertical component of the velocity of a projectile decreases as the projectile rises upward toward its peak.
Misconception: The acceleration of a projectile increases as the projectile falls downward from its peak.
Correct Concept: The vertical component of the velocity of a projectile increases as the projectile falls downward from its peak.
Misconception: The acceleration of a projectile depends upon the mass of the projectile.
Correct Concept: The acceleration of all projectiles on Earth is 9.8 m/s/s regardless of the mass of the projectile.
