# Is Negative Acceleration Always Indicative of Slowing Down?

• mncyapntsi
In summary, the conversation discusses the accuracy of statements regarding acceleration at different points in time. The first statement is deemed false by the speaker, while the rest are considered true. The concept of negative acceleration is also clarified.
mncyapntsi
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?

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

PeroK
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.

mncyapntsi
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.

mncyapntsi
Thanks for helping me think through that, and clearing it up!

PeroK
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.

mncyapntsi and PeroK

## 1. What is the difference between acceleration and speed?

Acceleration is the rate of change of an object's velocity, while speed is the rate of how fast an object is moving.

## 2. How are acceleration and speed related?

Acceleration and speed are related in that acceleration can cause a change in an object's speed. For example, if an object is accelerating, it will either speed up or slow down.

## 3. Can an object have a constant speed and still be accelerating?

Yes, an object can have a constant speed and still be accelerating if its direction of motion is changing. For instance, a car going around a curve at a constant speed is still accelerating because it is changing its direction of motion.

## 4. What is the unit of measurement for acceleration?

The unit of measurement for acceleration is meters per second squared (m/s²).

## 5. How can I calculate acceleration and speed?

Acceleration can be calculated by dividing the change in velocity by the change in time, while speed can be calculated by dividing the distance traveled by the time it took to travel that distance.

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