From 9ff4a1562a4f12ec5162fc7faab3e2029df811b6 Mon Sep 17 00:00:00 2001 From: Ceda EI Date: Mon, 18 May 2020 18:11:20 +0530 Subject: [PATCH] Add assignment 2 engg_mech --- engg_mech/assignment/t_two.tex | 135 +++++++++++++++++++++++++++++++++ 1 file changed, 135 insertions(+) create mode 100644 engg_mech/assignment/t_two.tex diff --git a/engg_mech/assignment/t_two.tex b/engg_mech/assignment/t_two.tex new file mode 100644 index 0000000..bcb9120 --- /dev/null +++ b/engg_mech/assignment/t_two.tex @@ -0,0 +1,135 @@ +\documentclass{article} +\usepackage{amsmath} +\usepackage{amssymb} +\usepackage{siunitx} +\usepackage{graphicx} +\usepackage{wrapfig} +\graphicspath{{./images/}} +\begin{document} +\title{Engineering Mechanics} +\author{Ahmad Saalim Lone, 2019BCSE017} +\date{17 May, 2020} +\maketitle +\section*{Question 1} +\subsection*{Question 1.a} +We shall balance the torque about $C$. $\angle ABC = \theta$, Tension in cable $=T$. +\begin{align*} + 240 (0.4) + 240 (0.8) &= T\sin{\theta} \times 0.18 \\ + T\sin{\theta} &= 1600 \\ + T \frac{0.24}{0.3} &= 1600 \\ + T &= 2000 +\end{align*} +\subsection*{Question 1.b} +On making FBD of bracket BCD.\@ + +\begin{align*} + x-component &= N_x = T\sin{\theta} = 1600 \\ + y-component &= N_y = T\cos{\theta} + 240 +240 = 1680 +\end{align*} + +\section*{Question 2} +\subsection*{Question 2.a} +We shall balance the torque about C +\begin{align*} + P \times 7.5 &= T \times 5 \\ + T &= 150 lb +\end{align*} +\subsection*{Question 2.b} +\begin{align*} + N_x \text{(reaction at C along x-axis)} &= - (P + T\sin{\ang{37}}) = -190 lb \\ + N_y \text{(reaction at C along y-axis)} &= - T \cos{\ang{37}} = -120 lb +\end{align*} +\section*{Question 3} +\subsection*{Question 3.a} +\[ + \alpha = 0 +\] +Balance torque about B +\begin{align*} + N_a \times 20 &= 75 \times 10 \\ + N_a &= 37.5 lb +\end{align*} +Balance torque about A +\begin{align*} + N_b \times 20 &= 75 \times 10 \\ + N_b &= 37.5 lb +\end{align*} +\subsection*{Question 3.b} +\[ + \alpha = \ang{90} +\] +Balance torque about A +\begin{align*} + N_b \times 20 &= 75 \times 10 \\ + N_b &= 37.5 lb +\end{align*} +Balance torque about B +\begin{align*} + N_a \times 12 &= 75 \times 10 \\ + N_a &= 62.5 lb +\end{align*} +\subsection*{Question 3.c} +\[ + \alpha = \ang{30} +\] +Balance torque about the mid point of horizontal rod +\begin{align*} + N_a \times 10 &= {(N_b)}_y \times 10 \\ + N_a &= {(N_b)}_y +\end{align*} +Balance torque about B +\begin{align*} + N_a \times 20 &= 75 \times 10 \\ + N_a &= 37.5 lb \\\\ + N_a &= N_b \cos{\ang{30}} \\ + N_b &= 43.30 +\end{align*} + +\section*{Question 4} +\subsection*{Question 4.a} +Balance torque about C +\begin{align*} + 120 \times 0.28 &= T \times \frac{150}{250} \times 0.2 + T \times \frac{150}{390} \times 0.36 \\ + 33.6 &= T \times 0.26 \\ + T &= 129.2 N \approx 130 N +\end{align*} +\subsection*{Question 4.b} +\begin{align*} + {(N_c)}_x &= T \times \frac{200}{250} + T \times \frac{360}{390} \\ + {(N_c)}_x &= 223 N \\ + {(N_c)}_y &= 120 - \left(T \times \frac{150}{250} + T \times \frac{150}{390}\right) \\ + {(N_c)}_y &= -7.21 N \\ + N_c &= \sqrt{223^2 + 7.21^2} N \\ + N_c &= 224 N +\end{align*} + +\section*{Question 5} +Balance torque about B +\begin{align*} + {(N_a)}_y \times 8 &= 4000 \times 2 \\ + {(N_a)}_y &= 1000 N +\end{align*} +FBD of Rod +\begin{align*} + 4000 &= {(N_A)}_y + {(N_B)}_y \\ + 4000 &= 1000 + {(N_B)}_y \\ + {(N_B)}_y &= 3000 \\\\ + {(N_B)}_y &= N_b \sin{\ang{60}} \\ + N_B &= 3465 \\ + {(N_A)}_x &= {(N_B)}_x \\ + {(N_A)}_x &= N_B \sin{\ang{30}} \\ + {(N_A)}_x &= 1732 +\end{align*} +\section*{Question 6} +First we have to calculate reaction at A +\begin{align*} + \sum F_x &= 0 \\ + 4000 \cos{\ang{30}} &= A_x \\ + A_x &= 3464 N +\end{align*} +\begin{align*} + \sum F_y &= 0 \\ + 6000 + 4000 \cos{\ang{30}} &= A_y \\ + A_y &= 8000 N +\end{align*} +\end{document}