Where did i go wrong?

Hi guys can u have a look at my working for question 81 and let me know where i went wrong.

I made the assumption that the minimum angle would be such that the vertical component of velocity would equal zero at a height of 3m.

Apparently the answer is A but i got D.

Hi guys can u have a look at my working for question 81 and let me know where i went wrong.

I made the assumption that the minimum angle would be such that the vertical component of velocity would equal zero at a height of 3m.

Apparently the answer is A but i got D.

I’m not sure what you did, but I just used trig.
Tanx=O/A
Arctan(O/A) = X
Arctan (6/3) = X
Arctan(2) = X

What did i miss?

It’s a triangle, the adjacent side is 6 units long, the opposite side is 3 units long.
I think you over complicated a simple question

But tan(x)=opposite/adjacent. In ur original post it appears that u used tan(x)=adjacent/opposite. Unless u used the other angle in the traingle. If so why did u use that angle as opposed to the one i have marked as theta on my diagram?

Sorry for all the questions this is something simple but for some reason its just not clicking.

Guess its the sunday feeling.

Hmmmm yes sorry I made a mistake it should just be arctan (3/6)
I even just put it into a triangle calculator online and it gave me an angle of arctan(1/2) so I don’t know why the answer is supposed to be A

You worked out the angle for the minimum velocity.

If the ball, in the limit, went infinitely fast, it would travel in a straight line to the top of the wall. And that would be when the angle is a minimum.

Is there working right. I think theres a mistake which propagates through to give an answer of 45 degrees

Is there working right. I think theres a mistake which propagates through to give an answer of 45 degrees

From the wording of the first sentence in the question, I get the impression it's been changed prior to publication. I go with arctan(1/2) as the minimum angle - though it's not actually achievable.

Question is a bit of a mess - I'd ignore it and move on.