The Student Room Group
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>

AS Level Maths Kinematics Q

https://imgur.com/a/XzWvOSP
I'm not quite sure how i) is 5 marks, I have tried differentiating it to find the velocity giving me 4t^3 - 16t = 0 and for ii) I differentiated the original formula twice to give me 32 m/s.
(edited 5 years ago)
Original post by Zain786H
<blockquote class="imgur-embed-pub" lang="en" data-id="a/5by15aL"><a href="//imgur.com/5by15aL"></a></blockquote><script async src="//s.imgur.com/min/embed.js" charset="utf-8"></script>
I'm not quite sure how i) is 5 marks, I have tried differentiating it to find the velocity giving me 4t³ - 16t = 0 and for ii) I differentiated the original formula twice to give me 32 m/s.


there's no attachment?
Reply 2
Avatar for Zain786H
Zain786H
OP
10
Original post by Anonymouspsych
there's no attachment?


fixed :smile:
Original post by Zain786H
https://imgur.com/a/XzWvOSP
I'm not quite sure how i) is 5 marks, I have tried differentiating it to find the velocity giving me 4t^3 - 16t = 0 and for ii) I differentiated the original formula twice to give me 32 m/s.


It does seem very easy for 5 marks...

You are given the displacement as a function of time so s(t)=t^4 - 8t^2 +16
You have done the correct thing by differentiating the displacement to get velocity as v(t)=s'(t) = 4t^3 - 16t and so v(2) = 0

However you won't get the full 5 marks as this isn't sufficient enough to answer the whole question. You have shown that at t=2 the particle is at rest but you also need to show when t=2 the particle is at O. So I'm sure you know what to do next

Your answer to ii is correct
(edited 5 years ago)
Reply 4
Avatar for Zain786H
Zain786H
OP
10
Original post by Anonymouspsych
It does seem very easy for 5 marks...

You are given the displacement as a function of time so s(t)=t^4 - 8t^2 +16
You have done the correct thing by differentiating the displacement to get velocity as v(t)=s'(t) = 4t^3 - 16t and so v(2) = 0

However you won't get the full 5 marks as this isn't sufficient enough to answer the whole question. You have shown that at t=2 the particle is at rest but you also need to show when t=2 the particle is at O. So I'm sure you know what to do next

Your answer to ii is correct

Am I meant to substitute t into the displacement formula giving me 0 also for I)?
Original post by Zain786H
Am I meant to substitute t into the displacement formula giving me 0 also for I)?


exactly
Reply 6
Avatar for Zain786H
Zain786H
OP
10
Original post by Anonymouspsych
exactly


that's great, thanks!

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you