Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025
Definition
vf, or final velocity, is a fundamental concept in the study of acceleration. It represents the speed or rate of motion of an object at the end of a given time period or distance traveled.
5 Must Know Facts For Your Next Test
vf is related to the equation of motion: $vf = v₀ + at$, where $v₀$ is the initial velocity, $a$ is the acceleration, and $t$ is the time elapsed.
vf can be used to calculate the distance traveled by an object undergoing constant acceleration using the equation: $
abla x = \frac{1}{2}(v₀ + vf)t$.
The sign of vf (positive or negative) indicates the direction of motion, with positive values representing motion in the positive direction and negative values representing motion in the negative direction.
vf is an essential parameter in the analysis of projectile motion, where an object is launched with an initial velocity and experiences acceleration due to gravity.
Understanding vf is crucial for analyzing the motion of objects in various applications, such as vehicle dynamics, sports physics, and the design of mechanical systems.
Review Questions
Explain how the final velocity (vf) is related to the initial velocity (v₀) and acceleration (a) of an object.
The relationship between final velocity (vf), initial velocity (v₀), and acceleration (a) is given by the equation: $vf = v₀ + at$. This equation shows that the final velocity of an object is determined by its starting velocity, the acceleration acting on it, and the time elapsed. By rearranging this equation, you can also calculate the time required for an object to reach a certain final velocity, given its initial velocity and acceleration.
Describe how the final velocity (vf) can be used to determine the distance traveled by an object undergoing constant acceleration.
The final velocity (vf) can be used, along with the initial velocity (v₀) and the time elapsed (t), to calculate the distance traveled by an object undergoing constant acceleration. The equation for this relationship is: $
abla x = \frac{1}{2}(v₀ + vf)t$. This equation shows that the distance traveled is proportional to the average of the initial and final velocities, as well as the time elapsed. By knowing any three of these variables, you can solve for the fourth, which is useful in a variety of physics problems involving motion under constant acceleration.
Analyze the significance of the sign of the final velocity (vf) and how it relates to the direction of motion.
The sign of the final velocity (vf) is an important indicator of the direction of motion. A positive value of vf indicates that the object is moving in the positive direction, while a negative value of vf indicates that the object is moving in the negative direction. This information is crucial for understanding the overall motion of an object, especially when analyzing problems involving projectile motion or the motion of objects under the influence of gravity. The sign of vf can also be used to determine the acceleration of the object, as the acceleration and final velocity must have the same sign if the object is undergoing constant acceleration.