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Straight-Line Motion: Connecting Position, Velocity, and Acceleration

Abigail Young

Abigail Young

6 min read

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Study Guide Overview

This study guide covers rectilinear motion, focusing on the relationship between position, velocity, and acceleration using derivatives. It explains how to determine speed and direction of motion from velocity, and how acceleration impacts velocity. Practice problems and solutions reinforce these concepts.

Straight-Line Motion: Connecting Position, Velocity, and Acceleration 🚗

Hey there, future calculus master! Ready to see how those derivatives you've been acing actually apply to the real world? Let's dive into rectilinear motion, where we'll use derivatives to connect position, velocity, and acceleration. It's like unlocking the secret language of movement! 🚀


🌊 Derivatives and Motion

Remember how the derivative gives you the instantaneous rate of change? Well, that's the key! In motion, we use derivatives to see how things are changing right now.

🛥️ Velocity and Speed

If x(t)x(t) is a function that tells you the position of an object at any time tt, then its derivative, x(t)x'(t) (or v(t)v(t)), gives you the velocity at that exact moment. Velocity is all about the rate of change of position with respect to time. It's also signed, meaning it tells you the direction of motion:

  • When v(t)v(t) is negative, the object is moving left: ➖ = ⬅️.
  • When v(t)v(t) is positive, the object is moving right: ➕ = ➡️.
Key Concept

Speed is just the magnitude (absolute value) of velocity. It tells you how fast something is moving, but not its direction. Think of it as the speedometer reading in your car.

🚤 Acceleration

Similarly, the derivative of the velocity function, v(t)v'(t) (or a(t)a(t)), gives you the acceleration of the object. Acceleration is the rate at which velocity changes. And guess what? Since v(t)=x(t)v(t) = x'(t), that means a(t)=x(t)a(t) = x''(t)! The second derivative of positio...

Question 1 of 11

🚗 A particle's position is given by x(t)=5t2+2t7x(t) = 5t^2 + 2t - 7. What is the velocity function, v(t)v(t)?

5t + 2

10t + 2

10t - 7

5t^3 + t^2 - 7t