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Rest and Change of Direction
A particle is instantaneously at rest when v=0; direction changes only if velocity changes sign.
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Rest and Change of Direction
What is it?
A particle is instantaneously at rest when v=0; direction changes only if velocity changes sign.
In simple words
- A particle is instantaneously at rest when v=0; direction changes only if velocity changes sign.
- Worked pattern: v=t-2 changes from negative to positive at t=2.
- Final check: domain, sign, notation, units, and reasonableness.
Important terms
Rest and change of direction: A particle is instantaneously at rest when v=0; direction changes only if velocity changes sign.
What you should learn
- State the rule for rest and change of direction.
- Solve a rest and change of direction problem step by step.
- Check the result, restrictions, notation, and units.
Recommended for Class 12
Full school-level explanation
A particle is instantaneously at rest when v=0; direction changes only if velocity changes sign.
CONCEPT AND RULE
A particle is instantaneously at rest when v=0; direction changes only if velocity changes sign.
METHOD
For rest and change of direction, identify the given information and required result. Select the matching definition or formula, state its conditions, substitute carefully, simplify one line at a time, and check.
WORKED EXAMPLE
v=t-2 changes from negative to positive at t=2.
COMMON MISTAKE
Write the governing rule before substitution, keep brackets and signs visible, and check that the answer satisfies all domain or interval conditions.
How to solve rest and change of direction
How it works
- Identify the mathematical objects, givens, restrictions, and required result.
- Choose and write the relevant definition, theorem, or formula.
- Substitute with brackets and carry out one justified step per line.
- Simplify, state the final answer clearly, and verify it in the original setting.
Remember
- Rest and change of direction
- rule
- worked example
- worked example
How the ideas connect
Worked example: v=t-2 changes from negative to positive at t=2.
Deeper understanding
Go beyond memorising Rest and Change of Direction. Connect the definition to reasons, relationships, exceptions, and exam wording.
How the ideas connect
Worked example: v=t-2 changes from negative to positive at t=2.
Common mistakes
Exam focus
Core Idea
Rule / Formula
Method
Worked Example
Exam focus
Quick revision
- Rest and change of direction
- rule
- worked example
- Rest and change of direction: A particle is instantaneously at rest when v=0; direction changes only if velocity changes sign.
- CONCEPT AND RULE: A particle is instantaneously at rest when v=0; direction changes only if velocity changes sign.
- METHOD: For rest and change of direction, identify the given information and required result. Select the mat
Write the governing rule before substitution, keep brackets and signs visible, and check that the answer satisfies all domain or interval conditions.
For long answers on Rest and Change of Direction: define clearly → explain the main parts → give one example → state one exam caution.
Exam Focus
Exam Focus
Important points
- Rest and change of direction
- rule
- worked example
- Rest and change of direction: A particle is instantaneously at rest when v=0; direction changes only if velocity changes sign.
Important formulas
- Rest and change of direction
- rule
- worked example
Common exam traps
- Write the governing rule before substitution, keep brackets and signs visible, and check that the answer satisfies all domain or interval conditions.
- A matching-looking formula is not valid until its conditions and domain have been checked.
Long question structure
Definition → key parts → example → exam caution
Common Mistakes
Common Mistakes
- Mistake
Write the governing rule before substitution, keep brackets and signs visible, and check that the answer satisfies all domain or interval conditions.
- Mistake
A matching-looking formula is not valid until its conditions and domain have been checked.
- Mistake
Write the governing rule before substitution, keep brackets and signs visible, and check that the answer satisfies all domain or interval conditions.
Revision Zone
60-Second Revision
Quick cues from this topic — use them for last-minute revision.
Rest and change of direction
rule
worked example
Rest and change of direction: A particle is instantaneously at rest when v=0; direction changes only if velocity changes sign.
A particle is instantaneously at rest when v=0; direction changes only if velocity changes sign.
- Definition
- A particle is instantaneously at rest when v=0; direction changes only if velocity changes sign.
- Critical warning
- Write the governing rule before substitution, keep brackets and signs visible, and check that the answer satisfies all d
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Exam Practice
Define
Q1. Define Rest and Change of Direction.
Explain
Q2. Explain: CONCEPT AND RULE.
Example
Q3. Give one clear example of Rest and Change of Direction and say why it fits.
Mistake
Q4. State one common mistake students make about Rest and Change of Direction.
Exam note
Q5. Write a short exam note on Rest and Change of Direction: definition, two points, one example.
Sources & References
School-standard facts for Matric and Intermediate. Original explanations — not copied from textbooks.