Need help with integration position vector question

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The discussion revolves around solving a physics problem involving an acceleration vector of -g\vec{j}. The key steps include recognizing that the velocity vector is the integral of the acceleration vector, leading to the equation -gt\vec{j}+ \vec{v}(0), where \vec{v}(0) is the initial velocity vector. To find \vec{v}(0), participants are advised to consider the components of a right triangle formed by the velocity's magnitude v and angle θ. After determining \vec{v}(0), the next step is to integrate the velocity function to find the position vector. The inquiry concludes with the original poster expressing gratitude for the guidance received.
P-Jay1
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Hi, can anyone help me with this question? Or give me some helpful links. I'm stuck!

It's question B2 part b. Thanks.

View attachment PHY116.pdf
 
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What is your difficulty? You are given an acceleration vector -g\vec{j} and, I presume, you know that the velocity vector is the integral of that -gt\vec{j}+ \vec{v}(0) where \vec{v}(0) is the "initial velocity" vector. You are given that by being told it has "magnitude v at an angle \theta to \vec{i}". Do you know how to write such a vector at that angle? (Think about the lengths of the legs of a right triangle with hypotenus of length v and one angle \theta.)

Once you have \vec{v}(0) add it to -gt\vec{j} to get the velocity vector as a function of t and integrate again.
 
This has answered my question. Thankyou!
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

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