گاما رو نصب کن!

{{ number }}
اعلان ها
اعلان جدیدی وجود ندارد!
کاربر جدید

جستجو

پربازدیدها: #{{ tag.title }}

جستجوهای پرتکرار

میتونی لایو بذاری!

One end of a light elastic string of natural length $0.4{\text{ }}m$ and modulus of elasticity $20{\text{ }}N$ is attached to a particle $P$ of mass $0.8{\text{ }}kg$. The other end of the string is attached to a fixed point $O$ at the top of a smooth plane inclined at ${30^ \circ }$ to the horizontal. The particle rests in equilibrium on the plane.

a) Calculate the extension of the string.

$P$ is projected from its equilibrium position up the plane along a line of greatest slope. In the subsequent motion $P$ just reaches $O$, and later just reaches the foot of the plane. Calculate

b) the speed of projection of $P$,

c) the length of the line of greatest slope of the plane.

پاسخ تشریحی :
نمایش پاسخ

a) $0.8g\sin 30 = 20e/0.4$

$e = 0.08{\text{ }}m$

b) $0.8{v^2}/2 + 20 \times {0.08^2}/\left( {2{\text{ }} \times {\text{ }}0.4} \right)$

$ = 0.8g\left( {0.4 + 0.08} \right)\sin 30$

$v = 2.1\left( 0 \right){\text{ }}m{s^{ - 1}}$

c) $0.8gd\sin 30 = 20{\left( {d - 0.4} \right)^2}/\left( {2 \times 0.4} \right)$

$25{d^2} - 24d + 4 = 0$

$d = 0.745{\text{ }}m$

تحلیل ویدئویی تست

تحلیل ویدئویی برای این تست ثبت نشده است!