Help understanding Acceleration

  • Context: High School 
  • Thread starter Thread starter Pin Head
  • Start date Start date
  • Tags Tags
    Acceleration
Click For Summary

Discussion Overview

The discussion revolves around understanding the concept of acceleration, particularly in the context of a car's motion. Participants explore the relationship between acceleration, velocity, and time, and clarify misconceptions about constant versus changing acceleration. The scope includes conceptual clarification and mathematical reasoning.

Discussion Character

  • Conceptual clarification
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant presents a calculation for acceleration, concluding it to be 2 m/s², and questions whether this implies increasing acceleration over time.
  • Another participant points out that the initial claim of constant acceleration is based on average values and does not account for changes in acceleration during the interval.
  • A participant clarifies that if acceleration is constant, the velocity changes at a constant rate, emphasizing that velocity at specific times should be expressed in m/s, not m/s².
  • Another participant explains the concept of acceleration as a change in velocity over time, suggesting that understanding it as "one meter per second per second" may help clarify the concept.
  • A further contribution discusses the practical understanding of acceleration in driving scenarios, noting that in typical problems, a single acceleration value is often assumed to be constant unless stated otherwise.

Areas of Agreement / Disagreement

Participants express differing views on the interpretation of constant versus changing acceleration. While some assert that the acceleration is constant, others challenge this by emphasizing the need for clarity on how acceleration may vary over time.

Contextual Notes

There are unresolved assumptions regarding the nature of the acceleration and the specific conditions under which it is measured. The discussion does not reach a consensus on whether the acceleration is indeed constant or if it varies.

Pin Head
Messages
23
Reaction score
0
Hi,
I just want to make sure I understand acceleration

α = Δv / Δt
α = vf - vi / tf - ti
α = 8m - 0m / 4s - 0s
α = 8m / 4s
α = 2 m/s2



So I know it has a constant acceleration of 2 m/s2
what I want to know does this mean that the object will increase in acceleration for example
I have two diagrams I created, now when the car accelerates does this mean at 1 second it is 2m/s2 and at 2 seconds it is increase by 4 m/s2 and at 3 seconds it has increased to 6 m/s2 and at 4 seconds it has increase to 8 m/s2

Am I understanding this correctly help would be appreciated
 

Attachments

  • acceleration1.jpg
    acceleration1.jpg
    4.3 KB · Views: 443
  • acceleration.jpg
    acceleration.jpg
    9 KB · Views: 320
Physics news on Phys.org
Pin Head said:
Hi,
I just want to make sure I understand acceleration

α = Δv / Δt
α = vf - vi / tf - ti
α = 8m - 0m / 4s - 0s
α = 8m / 4s
α = 2 m/s2

Unit of v is m/s not m.

Pin Head said:
So I know it has a constant acceleration of 2 m/s2

No, you don't know that. You computed the average acceleration based on initial and final velocity. You know nothing about how it changes in between.

Pin Head said:
what I want to know does this mean that the object will increase in acceleration
If the acceleration increases then it is not constant, as you claimed above.
 
Pin Head said:
So I know it has a constant acceleration of 2 m/s2
what I want to know does this mean that the object will increase in acceleration for example
I have two diagrams I created, now when the car accelerates does this mean at 1 second it is 2m/s2 and at 2 seconds it is increase by 4 m/s2 and at 3 seconds it has increased to 6 m/s2 and at 4 seconds it has increase to 8 m/s2

Am I understanding this correctly help would be appreciated


Acceleration (m/s/s OR m/s^2) describes changes in velocity m/s. If acceleration is constant in this scenario then velocity will be CHANGING at a constant rate. So at 1 second the velocity will be 2 m/s NOT 2 m/s^2 (this would be acceleration) and at 2 seconds the velocity will be 4 m/s NOT 4 m/s^2. Hope that helps
 
It might help to think of 1 m/s^2 as "one meter per second per second", meaning that every second, the velocity changes by 1 m/s.
 
Think of driving a car at a constant speed, say 40 miles/hour. or 40 k/hour. Then you press the gas pedal, going faster and faster and faster. You are now accelerating. You then press the gas pedal even more, your speed increase more, your acceleration increases.
Usually in an actual problem in a text or homework you are given just one acceleration, you can assume its a constant, or average, acceleration. If you are given more than one acceleration value, you need the time that acceleration lasts to get a distance.
 

Similar threads

Undergrad The rocket equation, one more time
  • · Replies 41 ·
2
Replies
41
Views
3K
High School A scenario of non-uniform circular motion
  • · Replies 4 ·
Replies
4
Views
905
High School Why higher speeds need more power if the backward force is the same?
  • · Replies 38 ·
2
Replies
38
Views
3K
High School Finding the spring constant of a rope
  • · Replies 67 ·
3
Replies
67
Views
7K
Undergrad Gearbox Gear ratio: How to get 60 rpm to 3500rpm? help please
  • · Replies 10 ·
Replies
10
Views
3K
High School How Does Liquid Density and Viscosity Influence Free Fall Braking?
  • · Replies 2 ·
Replies
2
Views
2K
Undergrad Change of coordinates in a potential energy field
  • · Replies 2 ·
Replies
2
Views
2K
Undergrad Help please -- Trying to figure out rake barge capacity and displacement
  • · Replies 8 ·
Replies
8
Views
2K
Undergrad Calculating Power Requirements for a Ski Tow Rope with Friction | 18.9% Incline
  • · Replies 15 ·
Replies
15
Views
3K
High School Lifting an object with a mass difference of just 1kg
  • · Replies 6 ·
Replies
6
Views
1K