Is Negative Acceleration Always Indicative of Slowing Down?

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Homework Help Overview

The discussion revolves around the concept of negative acceleration and its implications for an object's motion, particularly whether it always indicates that the object is slowing down. Participants are examining statements related to acceleration at specific time intervals and their truth values.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants are sharing their reasoning regarding the truth of various statements about acceleration, questioning the conditions under which acceleration can be considered negative or zero. There is a focus on the relationship between velocity and acceleration in terms of direction and magnitude.

Discussion Status

There is an ongoing exploration of the statements presented, with participants attempting to clarify their understanding of acceleration and its implications. Some guidance has been offered regarding the interpretation of negative acceleration in relation to velocity, but no consensus has been reached on the truth of all statements.

Contextual Notes

Participants are working under the assumption that the context involves a linear motion scenario, with specific time points being analyzed for acceleration values. The discussion reflects varying interpretations of the relationship between acceleration and velocity.

mncyapntsi
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Homework Statement
Which of the following statements are false:

The speed at 2.1 min is less than at 2.6 min.
The acceleration is zero at 0.5 min and 4.2 min.
The acceleration is non-zero at 6.2 min.
The acceleration is never negative.
The acceleration is non-zero at 2.3 min.

IMAGE BELOW
Relevant Equations
a(t) = dv/dt; v(t) = dx/dt; ...
I've written in that only the first statement was False, however my classmates aren't getting the same answer?
Please help clarify...

Screen Shot 2021-09-14 at 4.50.38 PM.png
 
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Can you explain why you think the rest are true?
 
PeroK said:
Can you explain why you think the rest are true?
Here is my reasoning:

The acceleration is zero at 0.5 min and 4.2 min: true because x(t)=constant so v(t)=0 so a(t)=0

i just rethought this one - false right?: The acceleration is non-zero at 6.2 min: false because x(t)=mx+p so v(t)=constant so a(t)=0

The acceleration is never negative: true bc nowhere is v(t)<0

i just rethought this one - false? The acceleration is non-zero at 2.3 min: false because x(t)=mx+p so v(t)=constant so a(t)=0
 
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mncyapntsi said:
The acceleration is never negative: true bc nowhere is v(t)<0
Negative acceleration means that the object is slowing down. Not that the velocity is negative.
 
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Right! So only one of them is true - the second one?
 
mncyapntsi said:
Right! So only one of them is true - the second one?
That's what I think.
 
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Thanks for helping me think through that, and clearing it up!:smile:
 
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PeroK said:
Negative acceleration means that the object is slowing down. Not that the velocity is negative.
Just to clarify, that is in the present context where the velocity is positive. More generally, slowing down means the velocity and acceleration have opposite sign.
 
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