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## Class 11 Physics (India)

### Course: Class 11 Physics (India)>Unit 6

Lesson 2: Average velocity and average speed

# Average velocity and speed worked example

Sal solves a word problem to find average velocity and speed of an object in one-dimension.

## Want to join the conversation?

• After Sal calculated the average velocity and rounded it off to 2 significant digits, shouldn't the calculated value be negative 0.033 instead of simply 0.033?
• There should be a note on the bottom right-hand corner that states "Sal rounds the -1/30 to 0.033, but forgets the negative sign."
• At , I thought it was suppose to be Xf - Xi. Why did you subtract all three numbers?
• he was trying to get the distance the pig traveled(displacement), which obtained by Xf-Xi as you said but this equation only works regarding position on a number line. He is trying to get the displacement by using the length the pig traveled, and he got the displacement correctly.
• I'm still confused about the difference between average velocity and average speed. Can anyone help me, please?
• Although it doesn’t help you understand the meaning behind the concept, one way I have of remembering which one applies to the one that’s a vector, displacement, and which one applies to the one that’s a scalar, distance traveled, is: Vector and velocity go together, and both start with “v”, while scalar and speed go together, and both start with “s”.
• in case of calculating average velocity , shouldn't the final position be -30m ,hence the displacement should be -30 - 20m = -50m? please explain me if i am wrong
• In the case you are talking about, you have taken the 20m part as the pig running in the negative direction while the question states that the pig ran to the right and rightwards has to be taken as positive. Hence the 20m will be positive and the answer will be negative 10m.
• What year in school do we learn this? What grade?
• in highschool (9th-12th) depends on what school district you may be in, just as an example the district I'm in does it 11th-12th grade
• How is rate different from speed?
• I'm not a physics student or anything so don't quote me on this but, I think rate is the amount of something per unit of time, while speed has to be distance per unit of time.
• Shouldn't the 0.033 be a negative 0.033
• He said that to one significant digit, 50/300 is approx .1. Should that not be rounded up to .2?
• Its because he said Two significant figures that are 1 and 7 in 0.17