Magnitude of velocity and acceleration

In summary: But I need to find t I presume and then I can find the magnitude of velocity, but I'm not sure how to find t. The whole question is... confusing.
  • #36
PeroK said:
I would just do it numerically. There is a way for solving cubic equations. Try googling if you interested. But, I'd just hit it with a spreadsheet.
Never done that before but I'll look into it. Won't that give multiple values for t?
 
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  • #37
JustDerek said:
Never done that before but I'll look into it. Won't that give multiple values for t?

I know almost nothing about numerical methods. There is something called the Newton-Rhapson method, which you could codify in a program or spreadsheet. But, you know, all you have to do is check increasing values of ##t## until you go past the point you want, then refine the increments until you've narrowed it down to the required number of decimal places.

It's going to be somewhere between 30-40 seconds I guess.

You should be able to see analytically that there is only one real solution:your cubic function is monotonic.
 
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  • #38
PeroK said:
I know almost nothing about numerical methods. There is something called the Newton-Rhapson method, which you could codify in a program or spreadsheet. But, you know, all you have to do is check increasing values of ##t## until you go past the point you want, then refine the increments until you've narrowed it down to the required number of decimal places.

It's going to be somewhere between 30-40 seconds I guess.

You should be able to see analytically that there is only one real solution:your cubic function is monotonic.
Thanks for all your help. I'll see what I can do from here. You've been a saint I'd give you +100 likes if I could
 
  • #39
JustDerek said:
Thanks for all your help. I'll see what I can do from here. You've been a saint I'd give you +100 likes if I could
One would do!
 
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  • #40
JustDerek said:
When it is at point A then VA=5m/s which increases at a rate of a=(0.06t)m/s2.
Derek

Derek, I apologize. :frown: I missed the fact that the acceleration is not a constant! It looks like you got the help you needed though.
 
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  • #41
That's OK. The intention to help was appreciated
 
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