Help with average speed/instantaneous speed

[Bensky]

Help with average speed/instantaneous speed! :(

Homework Statement

1. EDIT: Figured this one out, now I just need to know about the 2nd question about instantaneous speed.
2. What is its instantaneous speed at t = 20 s?

Homework Equations

v= change in x/change in t

The Attempt at a Solution

I have no idea how to do this. My textbook doesn't really cover this section well, and I'm just starting out in Physics.
I did v=2/20 and came out with .1, but I think it's wrong.

 

[FedEx]

Homework Statement

1. What is its average speed during the first 35 s?
2. What is its instantaneous speed at t = 20 s?

Homework Equations

v= change in x/change in t

The Attempt at a Solution

I have no idea how to do this. My textbook doesn't really cover this section well, and I'm just starting out in Physics.
I did v=2/20 and came out with .1, but I think it's wrong.

Is it average speed or average velocity.As it is a displacement versus time graph.

 

[Bensky]

Is it average speed or average velocity.As it is a displacement versus time graph.

Average speed. That's where I'm confused. Why would they give me that type of graph?

 

[Sourabh N]

Average speed is the area of the graph divided by the time.

 

[Bensky]

Average speed is the area of the graph divided by the time.

Ok, well I figured out the average speed by doing d/t I think. Either way, it told me I was right, so now I just have the instantaneous speed problem that I don't understand. D:

 

[Sourabh N]

instanteneous speed is defined as the tangent to the curve at that point(time).

 

[Bensky]

instanteneous speed is defined as the tangent to the curve at that point(time).

So I would use the slope formula to find it?

 

[Sourabh N]

Ya. How did u get the area under the curve.