Please help!

Please help me in the 7th question....

Note by A Former Brilliant Member
2 years, 7 months ago

No vote yet
1 vote

  Easy Math Editor

This discussion board is a place to discuss our Daily Challenges and the math and science related to those challenges. Explanations are more than just a solution — they should explain the steps and thinking strategies that you used to obtain the solution. Comments should further the discussion of math and science.

When posting on Brilliant:

  • Use the emojis to react to an explanation, whether you're congratulating a job well done , or just really confused .
  • Ask specific questions about the challenge or the steps in somebody's explanation. Well-posed questions can add a lot to the discussion, but posting "I don't understand!" doesn't help anyone.
  • Try to contribute something new to the discussion, whether it is an extension, generalization or other idea related to the challenge.
  • Stay on topic — we're all here to learn more about math and science, not to hear about your favorite get-rich-quick scheme or current world events.

MarkdownAppears as
*italics* or _italics_ italics
**bold** or __bold__ bold

- bulleted
- list

  • bulleted
  • list

1. numbered
2. list

  1. numbered
  2. list
Note: you must add a full line of space before and after lists for them to show up correctly
paragraph 1

paragraph 2

paragraph 1

paragraph 2

[example link](https://brilliant.org)example link
> This is a quote
This is a quote
    # I indented these lines
    # 4 spaces, and now they show
    # up as a code block.

    print "hello world"
# I indented these lines
# 4 spaces, and now they show
# up as a code block.

print "hello world"
MathAppears as
Remember to wrap math in \( ... \) or \[ ... \] to ensure proper formatting.
2 \times 3 2×3 2 \times 3
2^{34} 234 2^{34}
a_{i-1} ai1 a_{i-1}
\frac{2}{3} 23 \frac{2}{3}
\sqrt{2} 2 \sqrt{2}
\sum_{i=1}^3 i=13 \sum_{i=1}^3
\sin \theta sinθ \sin \theta
\boxed{123} 123 \boxed{123}

Comments

Sort by:

Top Newest

@Spandan Senapati

A Former Brilliant Member - 2 years, 7 months ago

Log in to reply

Ya I know this q.Follow Harsh s solution.And you will get it.And if any problem then tag me and I will post it.Ok

Spandan Senapati - 2 years, 7 months ago

Log in to reply

Hey Spandan ,AE can you guyz tell me good source for practicing mechanics questions, especially rotational mechanics?

Harsh Shrivastava - 2 years, 7 months ago

Log in to reply

@Harsh Shrivastava Irodov(that's too good a book as I felt for rotational mech),and hc verma is good as well.For more tough prob you can refer to 300 creative physics problems by Laszlo Holics.

Spandan Senapati - 2 years, 7 months ago

Log in to reply

@Spandan Senapati Yes irodovs questions are good they are good but they are repeated in many books.

Harsh Shrivastava - 2 years, 7 months ago

Log in to reply

@Spandan Senapati yes, i have done that book it's amazing.

A Former Brilliant Member - 2 years, 6 months ago

Log in to reply

@A Former Brilliant Member Complete??good.I just solve in leisure....

Spandan Senapati - 2 years, 6 months ago

Log in to reply

@Spandan Senapati nah, not completely though ;P

A Former Brilliant Member - 2 years, 6 months ago

Log in to reply

@A Former Brilliant Member I used to solve some each day before inpho but now I have made up a plan to complete It.

Spandan Senapati - 2 years, 6 months ago

Log in to reply

@Spandan Senapati nice , it's an awesome book , go for it.

A Former Brilliant Member - 2 years, 6 months ago

Log in to reply

@A Former Brilliant Member Then try this "A guide to physics problems"... May be the second part be a bit tough as its Mostly Quantum Electrodynamics,Quantum Mechanics and all those stuffs but part 1 is good...... You will surely like it..And also try the integral I have posted

Spandan Senapati - 2 years, 6 months ago

Log in to reply

@Spandan Senapati dekhunga abhi ke liye toh jee bhot h :P

A Former Brilliant Member - 2 years, 6 months ago

Log in to reply

@A Former Brilliant Member pdf h iskki ?

A Former Brilliant Member - 2 years, 6 months ago

Log in to reply

@A Former Brilliant Member No my sir had given me...Not now but do try after you go an iit

Spandan Senapati - 2 years, 6 months ago

Log in to reply

@Spandan Senapati Ya....that book is very good.

A Former Brilliant Member - 2 years, 6 months ago

Log in to reply

@Spandan Senapati yes sure , why not ? i'll be doing mechanics for next 3 days even though i have chem exam ;P

A Former Brilliant Member - 2 years, 6 months ago

Log in to reply

@Harsh Shrivastava Further you may try David morin and peter gnadig's book " 200 puzzling questions in physics"

A Former Brilliant Member - 2 years, 7 months ago

Log in to reply

@A Former Brilliant Member But answer to David Morin's questions are not available? Do u have them?

Harsh Shrivastava - 2 years, 7 months ago

Log in to reply

@Harsh Shrivastava I feel the questions in Problems section are good enough .These problems have detailed solution which should be enough I guess.

A Former Brilliant Member - 2 years, 7 months ago

Log in to reply

I got it. Will post a solution by night.

Harsh Shrivastava - 2 years, 7 months ago

Log in to reply

Use the fact that since we assume strings to be inextensible, velocity of M at bottommost point will be only in horizontal direction, and use constraint relation between the velocity of M and m by equating their velocities along the thread connecting them.Finally use energy conservation.

Harsh Shrivastava - 2 years, 7 months ago

Log in to reply

Thanks Harsh & Spandan.

A Former Brilliant Member - 2 years, 7 months ago

Log in to reply

Any suggestion on coordinate geometry, I am very weak in it?

Harsh Shrivastava - 2 years, 7 months ago

Log in to reply

TMH and archive will suffice.

A Former Brilliant Member - 2 years, 7 months ago

Log in to reply

Which part...I guess straight lines and circles you must be well acquainted with......Coordinate needs some heavy practice....Formulas and all those stuffs should be known all the time..?As such I don't follow any special book only fiitjee package.

Spandan Senapati - 2 years, 6 months ago

Log in to reply

Hey you like integrals.I have a good one1)int1/(a+b(1x))2dxint1/(a+b(1-x))^2dxwith x varying from 010-1.This is a Feynman's Puzzle.Looks easy but needs some more....

Spandan Senapati - 2 years, 6 months ago

Log in to reply

use the transformation x-> 1-x and then differentiate the function 1/(a+bx) wrt a and then done.

Harsh Shrivastava - 2 years, 6 months ago

Log in to reply

@Harsh Shrivastava OK ok.That will lead to answer of I=1/abI=1/ab.If a and b are of opposite sign then the integrals value is Negative (ab<0)(ab<0).But the integrand be a square the area can never be negative.How do you resolve this...Here you integrating through Singularities.Pretty much the same thing as dx/x2dx/x^2 integral from (-1 to 1) isn't -2.The function blows up when x-->0...That's why its a Feynman's Puzzle...Try using limits in integrand.

Spandan Senapati - 2 years, 6 months ago

Log in to reply

@Harsh Shrivastava And also try to read "Feynman's trick"of differentiation under the integral sign.You will surely like it.

Spandan Senapati - 2 years, 6 months ago

Log in to reply

@Spandan Senapati I just know how to apply it I don't know the technalities behind it, will study soon.

Harsh Shrivastava - 2 years, 6 months ago

Log in to reply

Hey in your q you talked abt Max area....I think it should be min.I did it as the req point of intersection is apq,a(p+q)apq,a(p+q) where the points P and Q are (ap2,2ap)(ap^2,2ap)and (aq2,2aq)(aq^2,2aq).Then the cond yields apq=1apq=-1.Vertex being (0,0)(0,0)The Area of PCQPCQ is a2pq(pq)a^2|pq(p-q)|.Puting pq=1/apq=-1/a And later applying AM-GM yields the ans as Min=1Min=1.a=1/4a=1/4 from y2=4axy^2=4ax

Spandan Senapati - 2 years, 7 months ago

Log in to reply

Yeah you are right, my mistake, edited!

Harsh Shrivastava - 2 years, 7 months ago

Log in to reply

@Harsh Shrivastava Ya I see the problem has been changed.Thanks....I was surprised because of the title "its right"....I accepted my ans to be wrong....

Spandan Senapati - 2 years, 6 months ago

Log in to reply

×

Problem Loading...

Note Loading...

Set Loading...