# Physics questions

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#1
I have worked out weight to be 823.2 and then converted that to 820.I worked out my resultant force as 1900n.Then I used f=ma and worked out acceleration as 22.61 the converted to 23. Then for my velocity I got 15.16575 and converted that to 15.
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1 year ago
#2
Just as a rule of thumb, leave your answer un-rounded until the very end just so that it is as accurate as possible.

So, first calculate the weight (w=mg), which comes to 823.2N

Then, find the resultant force of which is given by: F(resultant)=F(water)-W => 1900-823.2 = 1076.8N

Use Newton's Second Law (F=ma) to find the acceleration; which equals 12.819... ms^-2

Sub that into your 'suvat' equation with u=0, s=5 and a=12.819..., to find v.

Therefore, v = 11.322... ms^-1 => 11.3 ms^-1
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#3
But it says to round to 2sf at every calculation.
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1 year ago
#4
(Original post by Marcusmaths)
But it says to round to 2sf at every calculation.
Ah I didn’t see that.

But if it’s not specified I’d say always go for three. Do you understand how to do the question now?
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#5
(Original post by hthain14)
Ah I didn’t see that.

But if it’s not specified I’d say always go for three. Do you understand how to do the question now?
Yeah, but with the 2sf thing for every equation do you do like 9.8=10 then do the calculation or do you Round after doing the calculation?
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1 year ago
#6
(Original post by Marcusmaths)
Yeah, but with the 2sf thing for every equation do you do like 9.8=10 then do the calculation or do you Round after doing the calculation?
All the values given at the top of the page are already in 2 significant form.

9.8 in 2 sig figs is 9.8.
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#7
(Original post by hthain14)
All the values given at the top of the page are already in 2 significant form.

9.8 in 2 sig figs is 9.8.
What I mean Is like with 823.2, do I then convert that to 2sf and this goes for all of the calculations.
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