True or false velocity physics question double check

  • Thread starter Thread starter Melchior25
  • Start date Start date
  • Tags Tags
    Physics Velocity
Click For Summary

Homework Help Overview

The discussion revolves around a physics problem concerning the motion of an object along the x-axis, specifically focusing on its position, velocity, and acceleration at a given instant. The original poster seeks confirmation on the correctness of their answers regarding the object's state when it is motionless and has a specified acceleration.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • The original poster lists several statements about the object's motion and asks for validation of their truthfulness. Participants engage by confirming or disputing these statements based on their understanding of derivatives related to motion.

Discussion Status

Some participants provide feedback on the original poster's statements, with one confirming the first derivative's value and another challenging the interpretation of the second derivative. There is an ongoing exploration of the implications of being motionless and having a negative acceleration.

Contextual Notes

The original poster expresses uncertainty about their reasoning and the correctness of their answers, indicating a need for further clarification on the relationships between position, velocity, and acceleration.

Melchior25
Messages
30
Reaction score
0
So I just want to make sure I have the correct answers before I submit my question. So could anyone please just double check my answers?

Thanks

An object moves in one dimension along the x-axis. At some instant in time, the object is located at x = 5.2 m, is motionless, and has an instantaneous acceleration of -2.3 m/s2. What must be true about this object at this instant in time? (Select all that apply.)
The first derivative of a position vs. time graph at this point is zero. False
The second derivative of a position vs. time graph at this point is zero. True
The slope of a velocity vs. time graph at this point is positive. False
The slope of a velocity vs. time graph at this point is negative. True
The object is just about to start moving backwards. True
The object is just about to start moving forwards. False

Again, I just want to make sure these are right. I'm not sure if I am completely correct.
 
Physics news on Phys.org
1. True. Because motionless means not moving means velocity is zero means first derivative of position towards time (ie velocity) is zero.
 
2. False. The second derivative of position towards time means acceleration. at this point, the acceleration is not zero because it is given to you as -2.3 m/s^2.
 
Thanks, Leong. I was actually a bit unsure about the first two. I wrote the equations out but some how had a feeling that I wasn't doing something right.
 

Similar threads

  • · Replies 9 ·
Replies
9
Views
1K
  • · Replies 2 ·
Replies
2
Views
5K
  • · Replies 13 ·
Replies
13
Views
4K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 3 ·
Replies
3
Views
6K
Replies
12
Views
2K
  • · Replies 11 ·
Replies
11
Views
3K
  • · Replies 13 ·
Replies
13
Views
1K
  • · Replies 9 ·
Replies
9
Views
2K