2.2 
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1 - Science of Physics
2 - Forces and Motion      Chapter 2 at a glance      2.1 - Motion      2.2 - Force, momentum, and Newton's laws      2.3 - Circular motion      2.4 - Solving harder physics problems      2.5 - Chapter review3 - Energy Transformations4 - Waves and Sound
5 - Electricity and Magnetism
6 - Light and Optics
7 - The Atom
8 - Linear Motion
9 - Vectors and Forces
10 - Forces
11 - Newton's Laws and Gravitation
12 - Circular Motion and Gravitation
13 - Torque and Static Equilibrium
14 - Momentum and Collisions
15 - Angular momentum
16 - Power and Machines
17 - Harmonic Motion
18 - Waves
19 - Sound
20 - Electricity
21 - Electric and Magnetic Fields
22 - Electromagnetism and Induction
23 - Light and Color
24 - Geometrical Optics
25 - Electromagnetic Radiation
26 - The Properties of Matter
27 - Thermodynamics and Heat Transfer
28 - The Atom
29 - The Quantum Theory
30 - TBD
31 - TBD
32 - TBD
33 - TBD
34 - TBD
35 - TBD
36 - TBD
37 - The atomic nucleus and radioactivity
38 - Nuclear reactions
39 - Relativity
40 - Particle physics and the standard model
41 - Electronics (semiconductors)
42 - Nuclear technology
43 - Lasers and photonics
44 - Metals, alloys and materials science
45 - Communications technology
46 - Buildings and structures
47 - Energy technology
48 - Biophysics
49 - Matter and Energy, Space and Time
50 - Energy Transformations
51 - Nanotechnology
52 - Website Videos
53 - ExtraStuff
55 - Modeling Motion, Friction, and Center of Mass
56 - Work and the Conservation of Energy
Torque
What is torque? Forces can cause objects to move in a linear way but objects may also twist or rotate. Consider the two forces acting on the box in the diagram on the right. The net force is zero because the forces are equal and in opposite directions. However, the box rotates because there is a torque created by these forces. A torque is a twisting action created by both force and distance. Torque is caused by forces that act to twist or rotate an object
When does a force make a torque? A force creates torque when its line of action does not pass through an object's center of rotation. The line of action is an imaginary line in the direction of the force passing though its point of application. Both forces in the diagram create torque.
Torque calculator
(2.9) τ=r×F
τ  = torque (N m)
r  = distance from center to line of action (m)
F  = force (N)
Torque
How do I calculate torque? Torque is usually represented by the lower case Greek letter τ (“tau”). The torque τ is the lever arm r times the magnitude of the force F. The lever arm is the perpendicular distance from the center of rotation to the line of action of the force. If the line of action passes through the center of rotation, the lever arm is zero, and so is the torque, no matter how large a force is applied.
What are the units of torque? The units of torque are force times distance, or newton-meters. A torque of 20 N-m is created by a force of 100 N acting with a lever arm of 0.2 meters. Because torque is a product of two variables, it is possible to create the same torque with different forces. For example, a 20-newton force applied with a lever arm of 1 meter also produces a torque of 20 N-m.Torque from a force and the line of action
Are there other units for torque? In English units, torque is usually expressed in pound-feet. A torque of one pound-foot represents the twisting action of a one pound force with a lever arm of 1 foot.
Can the same force make different torques? Examples of positive and negative values for torque The torque from any force depends on the location of the center of rotation. The same force can produce a different torque with a different center of rotation. Torques can also be positive or negative depending on whether they tend to cause clockwise or counterclockwise rotation about any given center. Show
Test your knowledge Jamir is struggling to loosen a bolt with a short wrench. If he uses a longer wrench but pushes with the same force, what happens to the torque generated?
  1. Increases
  2. Decreases
  3. Does not change
  4. No torque is generated
Show

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