Question

http://papers.xtremepapers.com/CIE/Cambridge%20International%20A%20and%20AS%20Level/Mathematics%20(9709)/9709_w13_qp_43.pdf
Question number 7

Answer 1

Integrate the velocity function to get the distance :

\[\large 540 = \int\limits_0^{60} |k_1t - 0.005t^2|dt\]

Answer 2

as the question suggests, find \(\large k_1\) first

Answer 3

i solve this part i am stuck with ii) and iii)

Answer 4

i got k1=1/2 and k2=12sqrt60

Answer 5

how did u get k2 ?

Answer 6

i equalized the two spides and i set t=60, v(60)=v(60)
(1/2)(60)-0.005(60)^2=k2/sqrt(60)

Answer 7

okay, but how do you know that you need to equate the speeds ?

Answer 8

because they share the same time 60s

Answer 9

Ah okay !

Answer 10

for part ii, try :
\[\large d(t) = 540 + \int\limits_{60}^t\dfrac{k_2}{\sqrt{t}}~dt\]

Answer 11

540+k2(t)^-1/2
540+k2(t)^1/2/1/2
540+2k2(t)^1/2
540+2kt2(t)^1/2-2k2(60)^1/2=s
540+2(12(60)(t)^1/2-2(12(60)^1/2(60)^1/2)=s
540+24(60)^1/2-1440=s
24(60)^1/2-900=s

Answer 12

sorry 24(60)^1/2(t)^1/2

Answer 13

Yes! thanks ganeshie i just solved the question now thanks for helping :)

Answer 14

np :) looks good!!