# Curves on a Position time graph

Tags:
1. May 30, 2016

### qwertyqwert321

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution
I knew the answer was between A and B, but the inward curves and outward curves on the position time graph confused me , what exactly does it mean?
-does A have an increasing velocity and then B has a decreasing velocity? im really confused with the slopes

2. May 30, 2016

### andrewkirk

Yes.

I don't think any of the graphs are correct. The one that is the closest is still wrong because the absolute value of the gradient of the segment that is described as 'slow constant speed' is greater than that for the segment described as 'running'. They should replace 'runs' by 'strolls' or even 'crawls'.

I think the correct answer would have the first two segments of A followed by the last two segments of B.

3. May 30, 2016

### rcgldr

The answer is probably B. The problem statement doesn't state the acceleration is constant, so an initially higher amount of acceleration that reduces as the constant speed is approached would be allowed, so B's curve in position versus time during acceleration isn't an issue. (Consider the case of a sprinter taking off from blocks). This leaves the slower constant negative velocity followed by faster positive velocity to decide between A and B.

4. May 30, 2016

### andrewkirk

Great lateral thinking!