Determining instantaneous velocity and average velocity using a graph.

Click For Summary
The discussion focuses on calculating instantaneous and average velocity from a position-time graph of a rabbit in a tunnel. To find instantaneous velocity at specific times, users suggest using the slope of a tangent line at those points. For average velocity, the formula (Xfinal - Xinitial)/(t final - t initial) is recommended for different time intervals. Participants express difficulty in obtaining answers and seek assistance in clarifying their calculations. The conversation emphasizes the importance of showing work to receive targeted help.
Crescent
Messages
1
Reaction score
0
The position of a rabbit along a straight tunnel as a function of time is plotted in Fig. 2-26.
Here's the figure:
http://www.webassign.net/giancoli5/2_26.gif

Determine its instantaneous velocity at the following times.
(a) t = 5.0 s
(b) t = 30.0 s

Determine its average velocity between the following times.
(c) t = 0 and t = 5.0 s
(d) t = 25.0 s and t = 30.0 s
(e) t = 45.0 s and t = 50.0 sa) I tried to find the slope of the straight line through [0,20] seconds by taking two points in it and take delta x / delta t

b) I drrew a tangent line to the curve at t = 30 then find its slope.For c , d , & e the avg v is:

(Xfinal - Xinitial)/(t final - t initial)

but still, I could not find an answer for any of them. It seems as if nothing is working.
 
Last edited:
Physics news on Phys.org
Welcome to PF!

Hi Crescent! Welcome to PF! :wink:

Show us what you've tried, and where you're stuck, and then we'll know how to help! :smile:
 
Where is your working?
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

Similar threads

  • · Replies 9 ·
Replies
9
Views
1K
Replies
5
Views
2K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 8 ·
Replies
8
Views
2K
Replies
8
Views
1K
Replies
5
Views
1K
Replies
1
Views
2K
  • · Replies 15 ·
Replies
15
Views
3K
Replies
1
Views
2K
Replies
6
Views
2K