Sebuah cakram uniform yg r=0,12m,m=5kg diputar sdmikian rupa.sbuah tali dililitkan ditarik dgn gaya .... Question from @kurniayuki92

August 2018 2 72 Report

Sebuah cakram uniform yg r=0,12m,m=5kg diputar sdmikian rupa.sbuah tali dililitkan ditarik dgn gaya 20N.
a. Brpa Torsi yg dkrjakan pd cakram?
b. Prcepatan anguler?
c. Jka cakram mulai Dari keadaan diam, berapakah kec.angulernya setelah 3s?
d. Energi knetik setelah 3s?
e.momentum angular setelah 3s?
f. Sudut total yg ditempuh cakram selama 3s?

inoid Dik :
r = 0,12 m
m = 5 kg
F = 20 N

Dit :
a. τ
b. α
c. ω_t ⇒ t = 3 s, ω_0 = 0 rad/s
d. E_k ⇒ t = 3 s
e. L ⇒ t = 3 s
f. θ ⇒ t = 3 s

Jawab :
a) τ = r×F = 0,12 × 5 = 0,6 Nm

b) $I= \frac{1}{2}mr^2= \frac{1}{2}(5)(0,12)^2=0,036$
τ = Iα
$\alpha = \frac{\tau}I = \frac{0,6}{0,036} = \frac{50}3$

c) ${{\omega }_{t}}={{\omega }_{0}}+\alpha t=0+\frac{50}{3}\cdot 3=50\text{ rad/s}$

d) ${{E}_{k}}=\frac{1}{2}I{{\omega }^{2}}=\frac{1}{2}\left( 0,036 \right){{\left( 50 \right)}^{2}}=45\text{ J}$

e) L = mω = 5×0,036 = 0,18 kg/s

f) $\theta ={{\omega }_{0}}t+\frac{1}{2}\alpha {{t}^{2}}=0\times 3+\frac{1}{2}\times \frac{50}{3}\times {{3}^{2}}=75\text{ rad}$

0 votes Thanks 1

fitribunga53 Kalau tdk salah sih hasilnya 75 rad
caranya panjang

0 votes Thanks 0

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