FOCUSED REVIEW
Focused Review — Acceleration and Constant-Acceleration Motion — Foundational
Reinforce the highest-leverage ideas and representative problem-solving tools for Acceleration and Constant-Acceleration Motion.
TIME
Approximately 15 minutes
BEST FOR
Targeted reinforcement
FINISH WITH
A readiness check
After this focused review, you'll be able to...
reinforce the key relationships, apply them to representative problems, and identify what still needs work.
Choose how you want to review
Course Alignment
This Physics Sensei Topic Review is an independent learning resource. Use it to reinforce key concepts, prepare for homework, or review before a quiz or exam.
Related Unit Review: If you need to review the complete unit material, review Motion in One Dimension here →
RESOURCE: Physics Sensei Topic Review | TOPIC ID: MEC-U03-T02 | TOPIC: Acceleration and Constant-Acceleration Motion | PARENT UNIT: MEC-U03 — Motion in One Dimension | COURSE LEVEL: Foundational
BEST USED ✓ After learning the topic ✓ Before starting homework ✓ Before a quiz or exam
Your Review Plan
Complete these six stages in order. Each stage builds on the previous one and prepares you for the final readiness check.
6 Stages • Approximately 15 minutes.
Warm-Up Check
Before you begin, take a moment to see what you already remember. Do not worry about getting everything right. This is only a starting point.
ACTIVITY 1
Key Ideas
State the meaning in words.
What does an acceleration of −3 m/s² tell you about how velocity changes each second?
Reveal Answers
Velocity changes by −3 m/s each second.
Why it works: Acceleration is velocity change per unit time.
ACTIVITY 2
Common Mistakes
Check the sign logic before calculating.
A cyclist has v > 0 and a < 0. Is the cyclist necessarily moving backward? Explain.
Reveal Answers
No. Positive velocity means it is still moving in the positive direction; negative acceleration means its velocity is decreasing.
Why it works: Direction of motion comes from velocity; acceleration describes how that velocity changes.
ACTIVITY 3
Quick Application
Estimate the direction of change first.
A ball moving upward has positive velocity. Just before it reaches its highest point, what is the direction of its acceleration?
Reveal Answers
Downward. Gravity remains downward even while the ball is still moving upward.
Why it works: Acceleration due to gravity does not reverse at the top of the path.
Ready to strengthen your understanding?
You've refreshed what you already know. Next, you'll reinforce the essential concepts that will help you solve problems with confidence. Need to see the learning path again?
Core Concepts
Reinforce the two highest-leverage relationships, then use them in representative situations.
KEY CONCEPT 1
Acceleration and Sign
Acceleration measures the rate at which velocity changes. Its sign indicates the direction of the velocity change, not whether an object is automatically speeding up or slowing down.
a = Δv/Δt
Example: A velocity change from +10 m/s to +4 m/s over 3 s gives a negative average acceleration.
Sensei note: Always define the positive direction before interpreting signs.
KEY CONCEPT 2
Constant Acceleration
When acceleration is constant, velocity changes by equal amounts in equal time intervals. Position does not change by equal amounts because the velocity itself is changing.
v = v₀ + at
Example: Starting from rest with a = +2 m/s² gives velocities 0, 2, 4, 6 m/s after 0, 1, 2, 3 s.
Sensei note: Constant acceleration does not mean constant velocity.
Ready to apply these ideas?
You've reinforced the essential concepts. Now it's time to put them into practice by working through guided examples and building your problem-solving confidence. Need a quick reminder?
Guided Practice
Apply the reinforced ideas to two representative situations, then use the strategy card to check your setup.
PRACTICE 1
Guided Example
Follow the sign convention and identify the known quantities.
A scooter moves at +4 m/s and accelerates at +1.5 m/s² for 4 s. Find its final velocity.
Reveal Answers
v = 4 + (1.5)(4) = +10 m/s.
Why it works: Constant acceleration changes velocity by aΔt.
PRACTICE 2
Independent Check
Work independently; write the sign of each quantity before substituting.
A car moving at +12 m/s slows with constant acceleration −3 m/s². How long does it take to reach +3 m/s?
Reveal Answers
3 = 12 − 3t, so t = 3 s.
Why it works: The negative acceleration reduces the positive velocity by 3 m/s each second.
Ready to check your understanding?
You've practiced the essential skills with guidance. Now it's time to solve a few short problems on your own and confirm you're ready to move forward. Need a quick reminder?
Confidence Check
You've rebuilt the key ideas and practiced them with guidance. Now try these short questions on your own to check your understanding before moving on.
QUICK CHECK 1
Velocity Change
Calculate the acceleration.
Velocity changes from −2 m/s to −8 m/s in 3 s. What is the average acceleration?
Reveal Answers
a = [−8 − (−2)]/3 = −2 m/s².
Why it works: The velocity becomes 6 m/s more negative in 3 s.
QUICK CHECK 2
Speeding Up or Slowing Down
Decide using signs, not position.
At one instant v = +5 m/s and a = −2 m/s². Is the object speeding up or slowing down?
Reveal Answers
Slowing down.
Why it works: Velocity and acceleration have opposite signs, so speed decreases at that instant.
How did it go?
You've checked your understanding. Take one final look at the essential ideas before deciding what to do next. Need a quick reminder?
Summary
Before moving on, take one final look at the essential ideas you’ll want to remember.
KEY TAKEAWAY 1
Read the Signs
Acceleration describes the direction and rate of velocity change. Compare the signs of v and a to decide whether speed increases or decreases.
KEY TAKEAWAY 2
Constant Means Equal Velocity Changes
For constant acceleration, velocity changes linearly with time. Use a consistent sign convention from start to finish.
Next Step
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