مناقشة واجبات [phys 101] للترم 131

ماقصرت يا ابراهيم .. الله يعطيك العافية

 

I think The first question is the two bodies have the same inertia because the low of

inertia of a disk have varaibles only of (R) and (m) .Thank you

 

أتوقع يوم تجي تجيب ال w تحط w0 اللي طلعناها من قبل .... ما تحط زيرو و شكرا

 

Makes sense.

 

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A wheel of diameter 0.026 m has a 6.8-m cord wrapped around its periphery. Starting from rest, the wheel is given a constant angular acceleration of 2.9 rad/s2. The cord will unwind in how many seconds?






فيه إشكال..تحت الجذر لازم يكون 2.9 * 0.5
فقط إشكال في الكالكوليشن..

 

النجدة بالله يا شباب واحد يتأكد من الحلول و يجمعها برد واحد عن الحوسة xD

مشكورين جميعا على الجهد

 

ch10-lecture-03



A disk starts from rest and rotates around a fixed axis, subject to a constant net torque. The work done by the torque during the second 5 s is:






a. the same as the work done during the first 5 s

b. twice as much as the work done during the first 5 s

c. four times as much as the work done during the first 5 s

d. half as much as the work done during the first 5 s

e. one-fourth as much as the work done during the first 5 s






A thin circular hoop of mass 3.8 kg and radius 2.1 m is rotating about an axis through its center and perpendicular to its plane. It is slowing down at the rate of 8.9 rad/s2. The net torque (in SI unit) acting on it is:





A disk has a rotational inertia of 6.6 kg m^2 and a constant angular acceleration of 3.7 rad/s^2. If it starts from rest the work done (in J) during the first 4.3 s by the net torque acting on it is:




والله اعلى واعلم

واذا فيه تعليق او احد عنده معلومه او خطأ في احد الاسئله اتمنى يفيدنا

وشكرا...

 

قوود جووب

 

السؤال الثاني مو المفروض نحط angular acceleration سعني الفا = (a/r) ؟؟؟

 

وحدة التسارع المعطاة rad/s^2 .. لذلك اظن انها angular acc. وحل اخونا سليم .

 

شكررا لك توني انتبه

 

حياك الله

 

بالنسبة للسؤال الثاني

 

مرحبا اخوي ابو ساره القانون اللي معك لاي hoop about any diameter لكن المطلوب بالسؤال hoop about central axis

عندك الكتاب صفحة 255 الصوره a و h توضح لك الفكره لان القانون اللي معك يستخدم لحل مسائل اخرى وشكرا ...

 

طريقتي صحيحه وطريقتك صحيحه يعني ماث ضربت الطرف الثاني بـ 2 وقسمت على 2.9

اتمنى وضحت وشكرا ..

 

إبراهيم

 

T131-ch11-lec-01-Q2

A sphere of mass 2,129 kg rolls on a horizontal floor so that its center of mass has a speed of 0.46 m/s. How much average power (in W) is required to stop the sphere in 1.9 s?

P = w/t
w = (delta)K
v = wr
k = (1/2)Iw^2
I(sphere) = 2/5MR^2

K = (1/5)m(v^2) << After substitution

Thuse,
P = k/t

__________________

A solid cylinder of mass 58 kg and radius [r] m is rolled down from an incline plane of angle 57 degree. Find the magnitude of acceleration (in SI unit) of the ball.
I(cylinder) = 1/2 MR^2

a(com) = - g sin(theta)/1+0.5

 

^

مني متأكد من الأجوبة يا ريت تأكدولي صح ولا لا

 

Chapter 11 يا شباب.