## gandalfwiz 2 years ago Anybody here good at physics and curious to know how long it takes a speeding Moped to reach Ke$ha? • This Question is Closed 1. gandalfwiz The moped accelerates uniformly over a time of 5.21 seconds for a distance of 110 meters. I have to a) find the average velocity, b) find the velocity at 5.21 seconds, and c) determine acceleration of the Moped. 2. gandalfwiz I'm pretty sure that the average velocity is 21.11 m/s (distance/time), but I'm unsure how to solve the others. Help? 3. Broken_Fixer does the moped start from rest? 4. gandalfwiz I'm assuming so 5. Broken_Fixer My formula chart sez $\Delta d = v_i \Delta t + \frac{1}{2}a (\Delta t)^2$ and you know d, v_initial, and t, so it's easy to solve for "a" ... 6. ravi623 average velocity= (u+v)\2=21.21 m\s v=u+at u+v=42.22 m\s 7. Broken_Fixer final velocity is pretty fast, can we hope that Ke$ha won't be able to get out of the way of the speeding moped?

8. ravi623

42.22-u=u+at 2u=42.22-5.21 a

9. gandalfwiz

lol @ fixer... but your formula is way too intense for me :) I think that there's a way to figure it out without one other than the basics...

10. gandalfwiz

ravi: what do u and v stand for?

11. Broken_Fixer

i think ravi is saying that final velocity is twice average velocity (since initial velocity is zero), and than acceleration is (final velocity) / (time).

12. ravi623

a=(42.22-2u)\2 u=initial velocity v=final velocity a=acceleration

13. gandalfwiz

hold on... let me process that information...

14. gandalfwiz

ravi- how'd you get 21.21? My calculations give 21.11

15. ravi623

sir, it was written by mistake

16. gandalfwiz

okay, so it is 21.11? and then from there you said that velocity=initial velocity + acceleration * time?

17. ravi623

yeah

18. gandalfwiz

and after that was initial velocity + final velocity= 42.22 m/s. Where did 42.22 come from?

19. Tomas.A

everyone whos good at physics are at physics group

20. gandalfwiz

no one in the physics group :P

21. ravi623

distance traveled=(average velocity). time=110

22. sunsetlove

im glad some one could help u

23. Tomas.A

20ppl there

24. gandalfwiz

Ravi? Where's u go :(

25. ravi623

i am here

26. ravi623

u+v=42.22 v-u=5.21 a so adding these equation, we get 2v=42.22+5.21a

27. ravi623

v=(42.22+5.11a)\2

28. ravi623

a=(v-u)\t if moped started from rest then a=v\t=v\5.11

29. ravi623

now we have final equation for v v=( 42.22+5.11*(v\5.11) ) \ 2 solving this equation for v, we can find the value of final velocity .

30. ravi623

here average velocity= (u+v)\2