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Mechanics- velocity and acceleration

Its question 12. Iam not understanding how to solve 12(b)16065721199417237385983267666950.jpg
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(edited 3 years ago)

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For each vehicle, the distance is the area under the curve.
Reply 2
ok I will try. thanks! my question is do I have to take the values till t=12
Original post by Shas72
ok I will try. thanks! my question is do I have to take the values till t=12


(1) If that's your question, why didn't you post it in your original post?
(2) Have you actually read the question carefully? This (plus a little common sense) would tell you "t=12" is not relevant to part (b).

I wouldn't respond like this, if this wasn't what happens pretty much *every* time you post a question. You don't state what your actual problem is, and when you do, it becomes apparent you either haven't read the question properly or (as the thread continues) you haven't read people's suggestions properly.
Reply 4
I understood how to get the expression 40+20(t-4). I don't understand how is it 22(t-10)-1/2(t-10)^2
Original post by Shas72
I understood how to get the expression 40+20(t-4). I don't understand how is it 22(t-10)-1/2(t-10)^2

As previously posted, it is the area under the graph. Again, I ask: are you sure you have read the question properly?
Reply 6
yes I have read the question properly
Original post by Shas72
yes I have read the question properly

So what's the problem?
Reply 8
pls explain how to calculate the distance of the truck. I don't understand how to find the area under the curve for the truck
Original post by Shas72
pls explain how to calculate the distance of the truck. I don't understand how to find the area under the curve for the truck

Break the graph into regions you do understand how to find the area for (e.g. rectangles and triangles) and add them up.
Reply 10
I did that already. I don't understand how to get the expression 22(t-10)-1/2(t-10)^2. if possible pls show me a few steps. I will work on it
Original post by Shas72
~snip~
Original post by DFranklin
Break the graph into regions you do understand how to find the area for (e.g. rectangles and triangles) and add them up.
Try again, and this time break it up into rectangles and triangles like I said.

For the record, I'm had enough - I'm not going to keep wasting my time on someone who doesn't follow instructions, and for whom trying to get information feels like getting blood from a stone.
Reply 12
ok thanks will try myself. its a bit discouraging when you talk like this. The forum is meant for students who are willing to help others. its absolutely fine if you don't want to.
Original post by Shas72
ok thanks will try myself. its a bit discouraging when you talk like this. The forum is meant for students who are willing to help others. its absolutely fine if you don't want to.


I don’t think that is very fair of you - DFranklin indicated you should break down the area under the graph into rectangles and triangles and you responded with a graph that didn’t do that.

They have been giving you help, you just aren’t doing the steps they ask you to do.

The forums are not meant to replace school/tutors by teaching you to topics-they are simply to give a guiding hand.
Original post by GabiAbi84
I don’t think that is very fair of you - DFranklin indicated you should break down the area under the graph into rectangles and triangles and you responded with a graph that didn’t do that.
It's perhaps worth the OP noting I moderated this forum for several years, so I have a fairly good idea of how it's supposed to work.

At the same time, I would fully accept I was pretty harsh, but it feels nothing actually gets through to the OP. It's always "yes, you're right, I'll do that", and then in the very next post, they go back to the same behaviour.

They have been giving you help, you just aren’t doing the steps they ask you to do.

The forums are not meant to replace school/tutors by teaching you to topics-they are simply to give a guiding hand.
OP says they are homeschooled. But they're absolutely at the point (long past, in fact) where they need to think about paying a tutor.

Part of my frustration (which I suspect is shared by other heavy contributors) is that it doesn't feel the OP actually values the help. Oh, they say they do, but they can't be bothered to read responses, or post their thoughts, or make diagrams where they actually bother to use a ruler. I can't help feeling if they were paying cold hard cash they might be a little more mindful of the need to actually put some effort in themselves.
Reply 15
I completely understand that. And iam very well aware and iam not asking for more than a guiding hand. I have had extremely helpful discussions and people taking extra steps to help me out. only request is if someone can't help they can very politely deny or just not respond. iam very well aware that if someone is helping me out they are investing their valuable time and I respect that. Thanks!!
Original post by Shas72
I completely understand that. And iam very well aware and iam not asking for more than a guiding hand. I have had extremely helpful discussions and people taking extra steps to help me out. only request is if someone can't help they can very politely deny or just not respond. iam very well aware that if someone is helping me out they are investing their valuable time and I respect that. Thanks!!


But if someone gives you a direct instruction for the first step to follow and you Don’t do that then it’s frustrating for those trying to help. Why should anyone put in extra help when you are not willing to follow simple guidance?
Reply 17
iam not willing to continue this discussion as its leading nowhere. My only request is don't throw your frustration by being nasty. if somebody isn't understanding my advise I would just stop responding. As iam reiterating I have had very very encouraging and very very helpful discussions on this forum. I respect the way people invest their time giving a helping hand on this forum. Thanks anyways
Reply 18
Original post by Shas72
I understood how to get the expression 40+20(t-4). I don't understand how is it 22(t-10)-1/2(t-10)^2


Original post by Shas72
I did that already. I don't understand how to get the expression 22(t-10)-1/2(t-10)^2. if possible pls show me a few steps. I will work on it


What does your graph for the truck look like (plotted up to a time t which is greater than 10)?

Can you see from the graph where the number 220 comes from in the formula for the truck's distance, i.e. which section of the graph it corresponds to?

What part of the graph represents the remaining distance? What steps would you carry out to calculate that distance?
Reply 19
Original post by davros
What does your graph for the truck look like (plotted up to a time t which is greater than 10)?

Can you see from the graph where the number 220 comes from in the formula for the truck's distance, i.e. which section of the graph it corresponds to?

What part of the graph represents the remaining distance? What steps would you carry out to calculate that distance?


16066171957924299164075932887214.jpg get the total distance of the truck is a rectangle (22×10) + the area of the small trapezium. The small trapezium can be calculated as triangle and rectangle. That's the point iam not able to calculate. I have circled the area where Iam not able to calculate.
(edited 3 years ago)

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