July 13, 2020, 03:06:31 pm

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twelftholmes

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« Reply #3915 on: June 29, 2020, 10:04:09 pm »
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Hey!!
I have a question from Jamon Windeyer's awesome physics topic tests if that's okay

Here is the Q: https://imgur.com/a/EfhvX8o
Here is my attempted answer: https://imgur.com/a/kXLoz0e

So basically, in the back of the answers Jamon has put that we can solve this either using conservation of energy and work, or calculate the acceleration and then approach it as a projectile motion question. I don't feel confident with latter and my class hasn't done module 5 yet (we're doing the modules in the order 6, 8, 7, 5 oop) so I chose the former which I feel like I understand much at this point. However I got it wrong and I'm wondering if it's because of an error in my working out or understanding using the method I did, or if it's because I'm better off approaching it like a projectile motion question (like Jamon did in the back of the book, however I didn't understand that which is why I'm here haha). If someone wouldn't mind helping me figure out how to get the correct answer that'd be awesome.  (using the method I did if that's possible).

blasonduo

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« Reply #3916 on: June 29, 2020, 11:21:27 pm »
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Hey!!
I have a question from Jamon Windeyer's awesome physics topic tests if that's okay

Here is the Q: https://imgur.com/a/EfhvX8o
Here is my attempted answer: https://imgur.com/a/kXLoz0e

So basically, in the back of the answers Jamon has put that we can solve this either using conservation of energy and work, or calculate the acceleration and then approach it as a projectile motion question. I don't feel confident with latter and my class hasn't done module 5 yet (we're doing the modules in the order 6, 8, 7, 5 oop) so I chose the former which I feel like I understand much at this point. However I got it wrong and I'm wondering if it's because of an error in my working out or understanding using the method I did, or if it's because I'm better off approaching it like a projectile motion question (like Jamon did in the back of the book, however I didn't understand that which is why I'm here haha). If someone wouldn't mind helping me figure out how to get the correct answer that'd be awesome.  (using the method I did if that's possible).

Hey!
Just looking at the question given, it originally says half a meter apart, but the diagram shows it as a meter apart. (So there's a typo in the question!)

What distance did Jamon use? This may be the error, because at a quick glance I don't see anything wrong with your working!

EDIT: So I've checked out how Jamon has done his answer. In the first part he uses d = 0.5, but in the second part of the working he uses d = 1.

$\ v^2 = 0^2 + 2 \times 3.52\times 10^{15}$
There should be an additional factor of 0.5.

Doing this does indeed give the same answer that you have worked out
« Last Edit: June 29, 2020, 11:45:01 pm by blasonduo »
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