Refer to image: http://session.masteringphysics.com/problemAsset/1…
In this problem, you must express the angle (alpha) in the above equation in terms of (theta), (phi), and/or (pi) when entering your answers.
A. What is the torque (rA) about axis A due to the force (Fvector)?Express the torque about axis A at Cartesian coordinates (0,0). rA = ???
B. What is the torque rB about axis B due to the force Fvector? (B is the point at Cartesian coordinates (0,b), located a distance b from the origin along the y axis.) Express the torque about axis B in terms of F, theta, phi, pi, and/or other given coordinate data.
C. What is the torque rC about axis C due to Fvector? (C is the point at Cartesian coordinates (c,0), a distance c along the x axis.) Express the torque about axis C in terms of F, theta, phi, pi, and/or other given coordinate data.
What is the torque about axis D due to ? Aswer same as the previous problems.
Thank you for your help!
3 Answers

any torq is vector t=[r×F], where vector r is arm, vector F is force;
our F=F*(cos(θ), sin(θ), 0); A♠ r=0; t=0;
B♣ r=(0, b, 0); t/F=
│
i
j
│
<code> b</code><code> </code>
“0│ = (0, 0, bcos(θ)); t =Fb*cos(θ);│ cos(θ), sin(θ), 0│
C♣ r=(c, 0, 0); t/F=
│
<code>j</code><code> </code></code><code> </code>
k││
<code>c</code></code><code> </code><code>0</code>
│ cos(θ), sin(θ), 0│
D♣ r=(dcos(φ), dsin(φ), 0); t/F=
│
<code>j</code><code> </code></code><code> </code><code> </code>
``k││dcos(φ), dsin(φ), 0│ = (0, 0, dcos(φ)sin(θ) + dsin(φ)cos(θ))=
│ cos(θ),
0│sin(θ),
= (0, 0, dsin(φθ))=; t =Fd*sin(φθ);

Finding Torque Mastering Physics

Part A) 0
Part B) bFcos(θ)
Part C) cFsin(θ)
Part D) d*F*(φθ)
Source(s): Another Mastering Physics victim