What was the answer for 14(a)(iv)? (1 Viewer)

[LittlerCandy]

I'm not 100% on this one. I integrated the displacement equation I'd gotten from (iii) but then I subtracted the integration of the line y=5. Did anyone else do this? If not, what was the correct answer?

 

[Recondit]

Correct answer was 29m
Youre meant to integrate the v(t) function as this gives displacement (however you have to absolute value the area under the x-axis to give distance)

In simpler terms, Just draw v=10-2t on a graph from t=0 (v=10) to t=7 (v=-4) with t-int (v=0) at t=5
Then find area of triangle from t=0 to t=5 which is ABOVE the x-axis which is 25u² then find the area below the x-axis between t=5 to t=7 which is 4u²

Sum of areas is 29u² therefore 29m total distance travelled

 

[Menomaths]

Correct answer was 29m

 

[Shazer2]

Correct answer was 29m

Got 29m. I just did table of values for 0 to 7, and showed the distance travelled. Reckon I'll get marks?

 

[Recondit]

Got 29m. I just did table of values for 0 to 7, and showed the distance travelled. Reckon I'll get marks?

My friend did something similar to that... I think you should get it

 

[Menomaths]

Got 29m. I just did table of values for 0 to 7, and showed the distance travelled. Reckon I'll get marks?

That's the correct answer and you showed working, better than mine (which was just adding up the differences LOL) so you should get full marks for it.

 

[Recondit]

lOl I actually got this question wrong cos I calculated area under x-axis wrong

 

[Randox]

I got 29

 

[LittlerCandy]

So what was the method exactly??

Just saw the method above, my bad.

 

[lolwot]

lOl I actually got this question wrong cos I calculated area under x-axis wrong

same, hope i get 1 mark

edit: i really gotta get off this site

 

[Menomaths]

same, hope i get 1 mark

edit: i really gotta get off this site

You're not the only one lol

 

[Randox]

integrate velocity from 5 to 0 and add that answer to the absolute value integral of velocity from 5 to 7.

 

[JT145]

crap for some reason I got 30 I think

 

[Recondit]

same, hope i get 1 mark

edit: i really gotta get off this site

Did you get 39m? LOL same here with second comment

 

[lolwot]

Did you get 39m? LOL same here with second comment

i got 21 did it from 7 to 0 so it was like 25 + (-4), instead of 0 to 5 and 5 to 7

 

[LittlerCandy]

integrate velocity from 5 to 0 and add that answer to the absolute value integral of velocity from 5 to 7.

Thanks, this is the method I attempted. Poorly attempted I might add

 

[NFmusic1995]

i got 29, i did it manually from each second and hoping it wouldnt go backwrds withina decimal otherwise the method wouldnt work LOL