Essential University Physics
4th Edition
ISBN: 9780134988559
Author: Wolfson, Richard
Publisher: Pearson Education,
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Textbook Question
Chapter 11.2, Problem 11.2GI
The figure shows four pairs of force and radius vectors and eight torque vectors. Which numbered torque vector goes with each pair of force-radius vectors? Consider only direction, not magnitude.
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axis is directed perpendicular to the plane of a square as shown in the figure. Two forces, F₁ and F2, are applied to
diagonally opposite corners and act along the sides of the square, first as shown in part a and then as shown in part b of the figure. In
each case the net torque produced by the forces is zero. The square is 1.00 m on a side, and the magnitude of F₂ is two times that of
F₁. What are the distances a and b?
F₁
t
Axis
F₂
O a=0.50 m, b = 0.50 m
Oa=0.40 m, b = 0.50 m
O a 0.20 m, b = 0.40 m
a=0.40 m, b = 0.20 m
a = 0.40 m, b = 0.40 m
F₁
b
(b)
F₂
Torques and cross product
Sketch the following positions and forces F. Use the cross product of the unit
vectors to calculate the assocated torques around the origin. Check that your answer
is consistent with the right hand rule.
(a) r₁ = 3î + 2ĵ (m), F₁ = 2ĵ (N)
(b) 7₂ = 2î (m), F₂ = Î – Ĵ (N)
Which of the following statements are true?
The magnitude of torque is the same for any axis of rotation you choose.
The vector r points from the axis of rotation to the point where the force is applied.
The lever arm is the distance between the point where a force is applied and the axis of rotation.
Torque has units of N m.
If vectors r and F are parallel, the torque is largest.
If you point your fingers along the vector r and curl them in the direction of F, your thumb points in the direction of the torque.
Chapter 11 Solutions
Essential University Physics
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What is Torque? | Physics | Extraclass.com; Author: Extraclass Official;https://www.youtube.com/watch?v=zXxrAJld9mo;License: Standard YouTube License, CC-BY