Calculating Average Speed on a Road Trip | Physics Help for Beginners

Click For Summary
The discussion revolves around calculating the average speed of a road trip using given variables A and B, which represent adjustments to the average speeds for two segments of the trip. Participants emphasize the importance of clearly defining variables and their units in physics problems, noting that A and B should be dimensionless for proper calculations. The conversation includes step-by-step calculations, leading to a total travel time of 168.4 minutes, which converts to approximately 2.8066 hours. Ultimately, the average speed is calculated to be around 49.9 km/h when rounded to three significant figures. Clarity in problem formulation and unit conversion is highlighted as crucial for understanding physics concepts.
  • #31
.807.

Why are you dividing this? I'm just trying to fully understand the problem for the test! :)
 
Physics news on Phys.org
  • #32
Lana Elcic said:
.807.

Why are you dividing this? I'm just trying to fully understand the problem for the test! :)
Bystander said:
48.4/60 = ?
 
  • #33
2 hrs is 120 min, 48.4 min. is .8xxx hrs. --- ?
 
  • #34
Bystander said:
2 hrs is 120 min, 48.4 min. is .8xxx hrs. --- ?

.8066
 
  • #35
Total time in hours is then what?
 
  • #36
Bystander said:
Total time in hours is then what?
2.8066?
 
  • #37
Lana Elcic said:
So is it just 140 km / 2.48 hr = 56.452?
Nope. Right idea.
Lana Elcic said:
Doesnt 168.4 minutes convert to 2.48 hours?
Nope.
Lana Elcic said:
2.8066?
... and the answer is ...?

Sorry about all the distractions. I know it's enough to rattle anyone. Couple or three things to remember: 1) try to post in the HW forum (for physics questions, anyway); 2) one step at a time; 3) re-read the question to be certain you're answering what's been asked; 4) pay attention to details, particularly when converting units (minutes to hours is something public schools haven't done correctly for ~ 20 years); 5) PF busy season has just started the last week or two, and there can be a lot of help that just isn't.
 
  • #38
Bystander said:
Nope. Right idea.

Nope.

... and the answer is ...?

Sorry about all the distractions. I know it's enough to rattle anyone. Couple or three things to remember: 1) try to post in the HW forum (for physics questions, anyway); 2) one step at a time; 3) re-read the question to be certain you're answering what's been asked; 4) pay attention to details, particularly when converting units (minutes to hours is something public schools haven't done correctly for ~ 20 years); 5) PF busy season has just started the last week or two, and there can be a lot of help that just isn't.

It's okay I understand. Just trying to focus. Is the answer 49.882?
 
  • #39
Lana Elcic said:
Round your final answer to three significant figures.
You're in business.
 
  • #40
Bystander said:
You're in business.
So 49.9!
Yayyyyyy!
 
  • #41
Thread closed temporarily for Moderation...
 

Similar threads

Calculating Average Speed: Physics Homework Problem
  • · Replies 13 ·
Replies
13
Views
2K
Trying to get an average speed of 60 MPH
  • · Replies 8 ·
Replies
8
Views
3K
How to Calculate Average Velocity with Displacement & Speed?
  • · Replies 3 ·
Replies
3
Views
2K
I can't quite get this question.... (|Uav|)
  • · Replies 8 ·
Replies
8
Views
2K
How Do You Calculate Average Speed in Different Driving Conditions?
  • · Replies 9 ·
Replies
9
Views
2K
Vectors: Displacement, average velocity & speed
  • · Replies 7 ·
Replies
7
Views
2K
What is the average speed for the entire trip?
  • · Replies 2 ·
Replies
2
Views
4K
What is the displacement and average velocity of a classic car in a road rally?
  • · Replies 1 ·
Replies
1
Views
2K
What is the average speed of a car on a trip with varying speeds and distances?
  • · Replies 27 ·
Replies
27
Views
3K
Calculating Average Speed and Velocity for a Commuting Student
  • · Replies 2 ·
Replies
2
Views
3K