AP Physics B Kinematics Presentation #71
TLDRIn the absence of air resistance, the horizontal component of a projectile's velocity remains constant throughout its parabolic trajectory. This is due to the lack of external forces acting on the horizontal velocity, while gravity affects only the vertical component. The script clarifies that the horizontal velocity does not increase, decrease, or become zero, debunking common misconceptions about projectile motion. Understanding this principle is crucial for grasping the physics of parabolic motion.
Takeaways
- π The horizontal component of a projectile's velocity remains constant if there is no air resistance.
- π Choice A is incorrect because a projectile has a horizontal velocity; it does not start with zero velocity.
- π Choice B is correct as the horizontal velocity does not change during the projectile's flight due to the absence of horizontal forces.
- π Choice C is incorrect because there is no force that continually increases the horizontal velocity of the projectile.
- π Choice D is incorrect as there is no force acting on the projectile to continually decrease its horizontal velocity.
- π₯ Projectile motion requires both vertical and horizontal components of velocity to result in a parabolic trajectory.
- π The vertical component of velocity is affected by gravity, increasing as the object falls and decreasing as it rises back up.
- π At the peak of the projectile's trajectory, the vertical velocity is zero, but the horizontal velocity remains constant.
- π The absence of air resistance is crucial for the horizontal velocity to remain constant throughout the projectile's motion.
- π The parabolic path of a projectile is determined by the initial horizontal velocity and the acceleration due to gravity.
- π Understanding the separate components of velocity in projectile motion helps to analyze and predict the object's trajectory accurately.
Q & A
What happens to the horizontal component of a projectile's velocity when air resistance is ignored?
-The horizontal component of a projectile's velocity remains constant throughout its trajectory when air resistance is ignored.
Why is the horizontal velocity of a projectile constant during its motion?
-The horizontal velocity remains constant because there are no external forces acting in the horizontal direction to change it.
What is the effect of air resistance on a projectile's motion?
-Air resistance would affect both the horizontal and vertical components of a projectile's motion, but it is ignored in this scenario, so it does not influence the projectile's velocity.
Why is the option stating that the horizontal velocity is zero incorrect?
-The option stating the horizontal velocity is zero is incorrect because a projectile must have an initial horizontal velocity to follow a parabolic path; otherwise, it would simply fall straight down.
What is the role of the vertical component of velocity in projectile motion?
-The vertical component of velocity is affected by gravity, causing the projectile to accelerate downwards and decelerate upwards as it reaches its peak.
At what point during its trajectory does the projectile's vertical velocity become zero?
-The vertical velocity of the projectile becomes zero at its highest point, which is the peak of its trajectory.
What is the shape of the path followed by a projectile when thrown horizontally?
-The path followed by a projectile when thrown horizontally is a parabola, due to the combined effects of constant horizontal velocity and gravity-induced vertical acceleration.
How does the absence of external forces in the horizontal direction affect the projectile's motion?
-The absence of external forces in the horizontal direction means there is no acceleration or deceleration, so the horizontal velocity remains constant.
What would happen to the projectile's motion if there was a constant force acting in the horizontal direction?
-If a constant force acted in the horizontal direction, it would cause the projectile's horizontal velocity to change, altering its trajectory from a parabola to a different shape.
Can the horizontal component of a projectile's velocity increase on its own during its flight?
-No, the horizontal component of a projectile's velocity cannot increase on its own during its flight if air resistance and other external forces are ignored.
Why is the option stating that the horizontal velocity continually decreases incorrect?
-The option stating that the horizontal velocity continually decreases is incorrect because, without external forces, there is no mechanism for the horizontal velocity to decrease during the projectile's flight.
Outlines
π Projectile Motion and Horizontal Velocity
This paragraph discusses the behavior of a projectile's horizontal velocity when air resistance is ignored. It clarifies that the horizontal component of velocity (X-velocity) remains constant throughout the projectile's trajectory. The paragraph refutes the misconceptions that the horizontal velocity could be zero, continually increase, or continually decrease. It emphasizes that in the absence of external forces, such as air resistance, the horizontal velocity does not change, while the vertical component of velocity (Y-velocity) is affected by gravity, increasing as the projectile falls and decreasing on its ascent. The correct answer to the question posed is that the horizontal component of a projectile's velocity remains constant (B).
Mindmap
Keywords
π‘Projectile Motion
π‘Horizontal Component
π‘Vertical Component
π‘Air Resistance
π‘Parabolic Motion
π‘Cliff
π‘Velocity
π‘Acceleration
π‘Trajectory
π‘Peak
π‘Constant
Highlights
Ignoring air resistance, the horizontal component of a projectile's velocity remains constant during its parabolic motion.
Choice A is incorrect as the horizontal velocity is not zero in projectile motion.
Choice B is correct, stating that the horizontal velocity remains constant without any external acceleration.
Choice C is incorrect as there is no force acting to continually increase the horizontal velocity.
Choice D is incorrect as well, since there is no deceleration in the horizontal direction.
Projectile motion requires both vertical and horizontal components of velocity to result in a parabolic trajectory.
When an object is thrown horizontally, it has an initial horizontal velocity that is maintained throughout its flight.
The vertical component of velocity increases as the object falls due to gravity and decreases on its way up.
At the peak of its trajectory, the vertical component of velocity is zero, but the horizontal component remains unchanged.
The horizontal component of velocity does not change during the projectile's motion as there is no external force acting on it.
The parabolic path of a projectile is determined by the initial horizontal and vertical velocities and the acceleration due to gravity.
In projectile motion, the horizontal velocity is independent of the vertical motion influenced by gravity.
The concept of projectile motion is essential for understanding the physics of moving objects under the influence of gravity.
The horizontal component of a projectile's velocity is a key factor in determining the range and trajectory of the object.
Understanding the constant horizontal velocity in projectile motion is crucial for predicting the object's landing point.
The absence of external forces or acceleration in the horizontal direction ensures the horizontal velocity remains constant.
The vertical component of velocity changes due to gravity, while the horizontal component remains unaffected.
The transcript provides a clear explanation of the principles governing the horizontal component of velocity in projectile motion.
Transcripts
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