Can anyone help me with this question?

Original post by Jiffylemmon

22xs=t?

You've got the formula mixed up.

s=ut

u = 22
t = t

Reply 21

OP

Original post by notnek

You've got the formula mixed up.

s=ut

u = 22
t = t

Okay so it's s/22=t But how can I find s or t with only one piece of information? (It's really strange that I cannot not even come close to answering this question since I just answer an harder question before this that also requires the use of a time graph it was worth up to 12 marks and this is only 3).

(edited 8 years ago)

Reply 22

Original post by Jiffylemmon

Okay so it's 22/s=t But how can I find s or t with only one piece of information?

Sorry that's wrong.

s = ut.

You have said that u/s = t which is incorrect.

You should be finding the distance in terms of t. This means that you use 't' as the value for time.

s = ut

u = 22
t = t

So s = 22t.

The distance travelled is 22t. Does this make sense?

Reply 23

Original post by Jiffylemmon

Okay so it's s/22=t But how can I find s or t with only one piece of information? (It's really strange that I cannot not even come close to answering this question since I just answer an harder question before this that also requires the use of a time graph it was worth up to 12 marks and this is only 3).

It's not strange at all. This 3 mark question was designed for someone who had already drawn a speed-time graph.

Reply 24

OP

Original post by notnek

Sorry that's wrong.

s = ut.

You have said that u/s = t which is incorrect.

You should be finding the distance in terms of t. This means that you use 't' as the value for time.

s = ut

u = 22
t = t

So s = 22t.

The distance travelled is 22t. Does this make sense?

yes I'm sorry about that, i usually don't stay up this late doing homework. I was suppose to type it in the other way round my bad.
So now that I know 22t=s where should I go?

Reply 25

OP

Original post by notnek

It's not strange at all. This 3 mark question was designed for someone who had already drawn a speed-time graph.

But the other one also was designed for someone who had already drawn an time graph

Reply 26

Original post by Jiffylemmon

yes I'm sorry about that, i usually don't stay up this late doing homework. I was suppose to type it in the other way round my bad.
So now that I know 22t=s where should I go?

Next find the distance for the third region.

The time for this section is 120 - t - 30. Does this make sense?

So you have:

u = 22
v = 0
t = 90 - t

Can you find s?

Reply 27

Original post by Jiffylemmon

But the other one also was designed for someone who had already drawn an time graph

So for that one you were just lucky that another method could be used that was simple.

Reply 28

Original post by notnek

So for that one you were just lucky that another method could be used that was simple.

I got 75 seconds, is that right?

Reply 29

OP

Original post by notnek

Next find the distance for the third region.

The time for this section is 120 - t - 30. Does this make sense?

So you have:

u = 22
v = 0
t = 90 - t

Can you find s?

S=(22+0/2)x90-t? So s=45?

(edited 8 years ago)

Reply 30

Original post by Jiffylemmon

S=(22+0/2)x90-t?

I think I have the right answer, if you want I can post a full solution with explanations for each line of working.

Reply 31

Original post by Jiffylemmon

S=(22+0/2)x90-t?

Yes and that can be simplified.

Finally add up all the distances and set the sum equal to 2145 since this is the total distance.

Then solve to find t.

Reply 32

Original post by notnek

Yes and that can be simplified.

Finally add up all the distances and set the sum equal to 2145 since this is the total distance.

Then solve to find t.

For the record, I like what you're doing. You're not just telling him the answer, you're giving him hints :P

Reply 33

Original post by jacobe

I think I have the right answer, if you want I can post a full solution with explanations for each line of working.

Please don't do that. You can see how hard that Jiffylemmon has worked in this thread so let them finish it.

Plus it's against the rules to post full solutions.

Reply 34

OP

Original post by notnek

Yes and that can be simplified.

Finally add up all the distances and set the sum equal to 2145 since this is the total distance.

Then solve to find t.

Is s 45?

Reply 35

Original post by notnek

Please don't do that. You can see how hard that Jiffylemmon has worked in this thread so let them finish it.

Plus it's against the rules to post full solutions.

Ok. I think you're making it way too complicated though.

Reply 36