Question

Runner run in a straight line with the average velocity of 5m/s for 5min and then with an average velocity of 4m/s 4 minutes. Total displacement is 2460m. What is the average velocity during this time?

Answer 1

Average velocity = Total Displacement/Total time taken

=> 2460/9*60 = 4.55 m/s

Answer 2

suppose the goal is to run 5 km in 15 minutes. What average velocity must she have over the remaining portion of her run?

Answer 3

\[5km*\frac{1000m}{1km}=5000m\]
\[15min*\frac{60s}{1min}=900s\]

Answer 4

@Abhisar

Answer 5

In continuation to the first question ?

Answer 6

I guess. I have the answer if that helps. I just need to know how to get there.

Answer 7

ok, what's the answer ?

Answer 8

7.06m/s

Answer 9

I was thinking that maybe 5000m would be the new displacement. Or to subtract 5000m-2460m=2540m would be the new displacement... I'm not sure where I'm going with this

Answer 10

Since, runner has to run a total of 5000m and she/he has already covered 2540m. We will consider a displacement of 5000-2540m. Also he/she has to complete the whole 5000m in 15 mins. But he/she has already taken 5+4=9 mins. So he/she will have to complete 2550 m in 15-9=6 mins.

Velocity = Displacement/Time
=> 2550/6*60 = 7.08 m/s

Answer 11

where did you get 2250?

Answer 12

Sorry it's 2460

Answer 13

oh ok =) thanks!

Answer 14

No !
lol
It's 2540, 5000-2460=2540

Answer 15

oh shoot haha

Answer 16

So everything's clear now ?

Answer 17

very thank you =D

Answer 18

you're most welcome :)

Answer 19

Just to clear it out, the final step will be little tweaked.

Velocity = Displacement/Time => 2540/6*60 = 7.06 m/s

Answer 20

yupp got it