Unit of Torque

Torque

The rotating equivalent of linear force is defined as torque. The rotational axis is the point about which an item rotates.

Torque is sometimes referred to as the turning effect, rotating effect, force moment, or moment.

A point object is defined as a body whose magnitude is less than the movement of an object over a given distance. Kinematics is used to describe the motion of point objects in one, two, and three dimensions. Point objects are frequently made up of very large particles. Newton’s Law of Motion describes the rotational behaviour of these unbounded particles.

Torque is symbolised by the symbol .

Types of Torque

There are two types of torque: static and dynamic.

The term “static torque” refers to a torque that does not create an angular acceleration. Because the door does not rotate on its hinges despite the force applied, someone pushing on it applies a static torque to it. Because they are not accelerating, someone pedalling a bicycle at a steady speed is likewise applying a static torque.

A dynamic torque is carried by the drive shaft of a racing car accelerating from the start line because it must produce an angular acceleration of the wheels provided that the car is accelerating along the course.

The term used to describe torque can be a bit puzzling. Engineers frequently use the terms moment and moment of force interchangeably. The moment arm refers to the radius at which the force acts.

Torque Formula

Torque=Force × Distance 

Torque ()=rF sin 

Here,

r= radius

F= force applied

= angle between the lever arm and the line of action of force 

Measurement of Torque

The Newton-metre (Nm) is the SI unit for torque.

The Foot-pound is a common imperial unit. This is puzzling because the pound is sometimes utilised as a unit of mass and sometimes as a unit of force. The term pound-force refers to the force exerted by earth gravity on a one-pound object. The magnitude of these units is frequently equivalent to 1 Nm=1.74 ft.lbs.

In a non-rotating system, measuring a static torque is usually simple and involves measuring a force. The torque can be calculated immediately from the length of the moment arm. Torque measurement in a spinning system is much more complicated. One way involves monitoring strain in the metal of a torque-delivering drive shaft and transmitting the data wirelessly.

Some other units of Torque

1. Kgm2/s2 is the SI base unit of torque.
2. Torque is measured in dyne-centimetres (dyne.cm) in the CGS system 
3. Torque is measured in a variety of ways, including:

• inch-pound-force 
• foot-pounds-force 
• ounce-force-inches (ozf.in)
• pounce-force-feet (lbf.ft)

Applications of Torque

1. Lock and key: Torque is the twisting motion that is put inside a lock to open it.
2. Ferris wheel: The torque is in charge of spinning the wheel on its axis by pushing it around.
3. Old telephone: With the help of our fingertips, we can rotate the numerals on a dial clockwise and anticlockwise using torque.
4. Gyroscopes: A flywheel is a wheel-like disc mounted on an axle in a gyroscope. The axis of the flywheel, which is perpendicular to the rotor axis, rotates due to torque.
5. Seesaws: Seesaws demonstrate the operation of the torque’s two most important components: force and moment arm. The seesaw’s balance point is the pivot point. Heavyweights can minimise torque by sitting closer to the point, whereas lightweights can do the opposite.
6. Hinged doors: The hinged door opens and closes due to torque at the pivot point, which is the hinge. If you put force near the door’s hinges, it will not open since the torque force is insufficient.

Importance of Torque

1. The concept of rotational motion of rigid bodies is explained by torque.
2. The idea of torque can be used to determine the direction and aim of a force applied to a body.
3. It also regulates whether a body moves clockwise or anti-clockwise.
4. When a body rotates, torque also determines the angular acceleration.

Important points regarding Unit of Torque

1. Rather than providing uniform rotation, torque contributes in the creation of angular acceleration in a body.
2. The torque formed is proportional to the force and distance applied.
3. Torque is the moment of force applied to the rotating axis and directed toward the object’s centre.
4. Torque is sometimes referred to as the turning effect, rotating effect, force moment, or moment.

Role of Torque in rotational kinematics

Torque replaces force in linear kinematics in rotational kinematics. Newton’s 2nd law of motion (F=ma) has a direct equivalence.

τ=Iα

The angular acceleration ( α )is given here. I is the rotational inertia of a rotating system, which is determined by the system’s mass distribution. The greater the I , the more difficult it is for an object to get angular acceleration. 

Rotational Equilibrium

The concept of rotational equilibrium is the same as Newton’s first law for a rotary system. Unless it is acted on by an external torque, an object that is not rotating stays that way. Similarly, an object rotating at constant angular velocity will continue to revolve until acted on by an external torque.

The concept of rotational equilibrium comes in help when dealing with problems involving several torques operating on a rotating component. It’s the net torque that matters in this case. When the net torque of a rotatable item is zero, it is in rotational equilibrium and unable to gain angular acceleration.

Conclusion

Torque, also known as force moment, is the tendency of a force to spin the body to which it is applied in physics. The torque is equal to the magnitude of the component of the force vector located in the plane perpendicular to the axis multiplied by the shortest distance between the axis and the direction of the force component with respect to the axis of rotation.