Question

The position of a particle moving along a line is given by

Answer 1

\[s(t)=2t^3-24t^2+90t+7\]

Answer 2

for what values t is the speed of particle increasing

Answer 3

\[s'(t) \implies velocity \space \space s''(t) \implies acceleration\]

Answer 4

ya i got a(t)=0 i got 4

Answer 5

as critical point

Answer 6

ds/dt=6t^2-48t+90
thus
d^2s/dt^2=12t-48 => aceleration is greater than zero when t>4

Answer 7

well first get the turning point,
you mean s'(t)=0

Answer 8

no i mean s''(t) gives acceleration =0 will give us information about velocity

Answer 9

yes so you got 4 right

Answer 10

yes

Answer 11

So yea it is when t>4 that the acceleration is postivei .e. speed increases

Answer 12

yes

Answer 13

no that not the answer i am looking for

Answer 14

Well its the right one...

Answer 15

but the answer is 3<t<4 and t>5 ( i was shocked !!!!

Answer 16

is it possible that this is wrong?

Answer 17

@hartnn

Answer 18

graph increasing
the speed inceases when the grapg rises so x<a and x>b

Answer 19

Okay well 3 and 5 are the critical points of the velocity