# Need some help: Reading a Velocity versus time graph

1. May 30, 2015

### Ayesha Shafique

Member warned about posting questions of substandard quality (no effort shown and image upside down).
1. At which points are velocity and acceleration the greatest?

2. Please check the attachment to see the graph.

3. I tried to solve it but i couldn't get to any conclusion.

Last edited by a moderator: May 30, 2015
2. May 30, 2015

### CWatters

You have circled two answer. Which do you think is correct and why?

3. May 30, 2015

### Ayesha Shafique

I have not circled these answers. This page is not mine I have taken it from someone for practice.

4. May 30, 2015

### ArmanCham

Graph is velocity-time graph.For max velocity we need to think wheres the max point in the graph.For accelaration we need to think "In which point the derivative of function gets max value ?"

5. May 30, 2015

### Ayesha Shafique

But what will be the answer

6. May 30, 2015

### ArmanCham

Look the graph.Max velocity means (theres a "x" point which "y" get max value)
Accelarations means "theres a point which we drove a slope in that point we get max value" I cant give you the answer its forbidden I guess.And you can think it.You can understand better If you think yourself.

7. May 30, 2015

### Ayesha Shafique

So
Then the answer is from R to T that is option B.

8. May 30, 2015

### ArmanCham

T is correct but R is not corect look again

9. May 30, 2015

### Ayesha Shafique

S to t that is option c

10. May 30, 2015

### ArmanCham

Thats right

11. May 30, 2015

### HallsofIvy

I don't know what you mean by "S to T". The question is asking for two points answering two questions, not for an interval. Since the graph is of "velocity versus time" the greatest velocity is where the graph is highest. What point is that? Since the problem has "Velocity Acceleration" in that order, this point should be first. The greatest acceleration occurs where the graph is steepest. That's not quite so obvious but still should be fairly easy to see. That point is second. "C" is NOT correct.

12. May 30, 2015

### ArmanCham

I didnt see that first point will be velocity and second will be accelaration .The answer is A I am so so sorry.I miss it

Last edited: May 30, 2015
13. May 30, 2015

### HallsofIvy

I said " the greatest velocity is where the graph is highest." If you believe that point R is where the graph is highest then you do not know how to read a graph. You need to talk to your teacher about this because he/she is assuming you have a skill that you do not have.

14. May 30, 2015

### Ayesha Shafique

Thanks for your guidance but I would like to inform you that I am only 14 years old and have just started to study physics. I was a bit confused with question because I hadn't studied yet how to figure out where the acceleration is highest in a graph. I guess i am allowed to make mistakes because I didn't know about this and therefore I asked for the help. Please be sure before saying something about anyone. Anyways thanks for your help and guidance now I have come to know what this means.

15. May 30, 2015

### CWatters

Have a think about the definitions of Distance, Velocity and Acceleration and how they are related....

Velocity = ΔDistance/ΔTime

So on a graph showing distance vs time the slope of the line at any point is the velocity.

Acceleration = ΔVelocity/ΔTime

So on a graph of Velocity vs time the slope of the line at any point is the acceleration.

So on your graph where is the slope at a maximum?

16. May 30, 2015

### Staff: Mentor

Then you should not have claimed to be 18 on your profile. We value honesty on this forum.