솔루션피아

$$ \begin{cases} \theta&=2.5\degree\\ mg&=69\ut{N}\\ g&=9.80665\ut{m/s^2}\\ \end{cases} $$ $$\Sigma \vec F = m\vec a,$$ $$ \begin{aligned} m a &= mg\sin\theta-f\\ f&=mg\sin\theta-ma\\ &=69 \sin2.5\degree-\frac{1380000}{196133}a \end{aligned} $$ $$\ab{a}$$ $$v=0,a=0$$ $$ \begin{aligned} f&=69 \sin2.5\degree\ut{N}\\ &\approx 3.009737728208184\ut{N}\\ &\approx 3.0\ut{N}\\ \end{aligned} $$ $$\text{D..

$$ \begin{cases} m&=1\ut{kg}\\ R&=6.40\times10^6\ut{m}\\ v&=465\ut{m/s}\\ F_0&=9.8\ut{N}\\ \end{cases} $$ $$\ab{a}$$ $$ \begin{aligned} \Sigma F_R &= \frac{mv^2}{R}\\ &=\frac{8649}{256000}\ut{N}\\ &=0.03378515625\ut{N}\\ &\approx 33.8\ut{mN}\\ \end{aligned} $$ $$\ab{b}$$ $$ \begin{aligned} \Sigma F_R&= mg-F_N\\ F_N&=mg-\Sigma F_R\\ &=\frac{2500151}{256000}\ut{N}\\ &=9.76621484375\ut{N}\\ &\appro..

$$ \begin{cases} mg&=220\ut{N}\\ \mu_s&=0.41\\ \mu_k&=0.32\\ g&=9.80665\ut{m/s^2} \end{cases} $$ $$\ab{a}$$ $$ \begin{aligned} f_{s\max}&=\mu_s mg\\ &=\frac{451}{5}\ut{N}\\ &=90.2\ut{N}\\ &\approx 90\ut{N}\\ \end{aligned} $$ $$\ab{b}$$ $$ \begin{aligned} f_k&=\mu_k mg\\ &=\frac{352}{5}\ut{N}\\ &=70.4\ut{N}\\ &\approx 70\ut{N}\\ \end{aligned} $$ $$\ab{c}$$ $$\Sigma \vec F = m\vec a,$$ $$ \begin{a..

(풀이자주:문제의 의도가 3주기를 원주율로 두라는 경우로 보입니다. 해당 풀이를 별첨합니다.) $$ \begin{cases} m&=2.0\ut{g}\\ R&=5.0\ut{cm}\\ 3T_1&=3.14\ut{s}\\ g&=9.80665\ut{m/s^2} \end{cases} $$ $$\ab{a}$$ $$ \begin{aligned} v_1&=\frac{2\pi R}{T_1}\\ &=\frac{1500\pi}{157}\ut{cm/s}\\ &\approx 30.015216435571272\ut{cm/s}\\ &\approx 30\ut{cm/s}\\ \end{aligned} $$ $$\ab{b}$$ $$a_R = \frac{{v_1}^2}{R},$$ $$ \begin{aligned} a_R&=\frac{4500..

$$ \begin{cases} \theta&=40.0\degree\\ \mu_k&=0.0400\\ m&=85.0\ut{kg}\\ A&=1.25\ut{m^2}\\ C&=0.140\\ \rho&=1.20\ut{kg/m^2}\\ \end{cases} $$ $$\Sigma \vec F = 0 \Harr \Delta \vec v=0,$$ $$ \begin{cases} \Sigma F_x &= 0\\ \Sigma F_y &= 0\\ \end{cases} $$ $$D=\frac{1}{2}C\rho Av^2,$$ $$ \begin{cases} 0 &= mg\sin\theta-\mu N-\frac{1}{2}C\rho Av^2\\ 0 &= N-mg\cos\theta\\ \end{cases} $$ $$\ab{a}$$ $$ ..

$$ \begin{cases} m&=2.8\ut{kg}\\ \theta&=30\degree\\ F&=15\ut{N}\\ \mu&=0.25\\ g&=9.80665\ut{m/s^2} \end{cases} $$ $$\ab{a}$$ $$ \begin{aligned} f&=\mu N\\ &=\mu(F\sin\theta+mg)\\ &=\frac{7 g}{10}+\frac{15}{8}\\ &=8.739655\ut{N}\\ &\approx 8.7\ut{N}\\ \end{aligned} $$ $$\ab{b}$$ $$\Sigma F=ma$$ $$ \begin{aligned} a&=\frac{F\cos\theta-\mu(F\sin\theta+mg)}{m}\\ &=\frac{1}{112} \(-28 g+300 \sqrt{3}..

$$ \begin{cases} \theta&=30\degree\\ \mu_1&=\mu\\ \mu_2&=0\\ t_1&=2t_2 \end{cases} $$ $$S=v_0t+\frac{1}{2}at^2,$$ $$S=(0)t+\frac{1}{2}a{t}^2$$ $$a=\frac{2S}{t^2}$$ $$ \begin{aligned} a_2&=\frac{2S}{{t_2}^2}\\ a_1&=\frac{2S}{(2t_2)^2}=\frac{1}{4}a_2 \end{aligned} $$ $$\Sigma \vec F = m\vec a,$$ $$ \begin{aligned} \Sigma F_2 &= m a_2\\ m a_2 &= mg\sin\theta\\ a_2&=g\sin\theta=\frac{g}{2}\\ a_1&=\f..

$$\Sigma \vec F = m\vec a,$$ $$ \begin{cases} m a &= mg\sin\theta-\mu_k N\\ 0 &= N-mg\cos\theta\\ \end{cases} $$ $$ a=g(\sin\theta-\mu_k\cos\theta) $$

$$ \begin{cases} v&=80.0\ut{km/h}=\frac{200}{9}\ut{m/s}\\ R&=350\ut{m}\\ m&=55.0\ut{kg}\\ \end{cases} $$ $$\ab{a}$$ $$ \begin{aligned} \Sigma F_R &= \frac{mv^2}{R}\\ &=\frac{44000}{567}\ut{N}\\ &\approx 77.60141093474427\ut{N}\\ &\approx 77.6\ut{N}\\ \end{aligned} $$ $$\ab{b}$$ $$ 90\degree $$

$$ \begin{cases} m_1&=30\ut{kg}\\ m_2&=15\ut{kg}\\ \mu_s&=0.60\\ \mu_k&=0.40\\ F&=100\ut{N}\\ g&=9.80665\ut{m/s^2} \end{cases} $$ $$\Sigma \vec F = m\vec a,$$ $$ \begin{cases} \Sigma F_{1x} &= m_1 a_1\\ \Sigma F_{1y} &= 0\\ \Sigma F_{2x} &= m_2 a_2\\ \Sigma F_{2y} &= 0\\ \end{cases} $$ $$ \begin{cases} m_1 a_1 &= -f\\ 0 &= N_1-N_2-m_1g\\ m_2 a_2 &= -F+f\\ 0 &= N_2-m_2g\\ \end{cases} $$ $$ \begin..