Difference Between Torque and Horsepower

Torque vs Horsepower

Torque and horsepower are two phenomena encountered in mechanics. This article will compare the two phenomena and present their differences in a simple way for the benefit of the readers.

What is Torque?

Torque is experienced in simple day-to-day activities such as turning a doorknob, fastening a bolt, turning the steering wheel, paddling a bicycle or even turning your head. There is a circular or rotational movement in all these activities. It can be shown that every movement where there is a change in the angular momentum there is always a torque acting upon the object. A torque is generated by a pair of forces, similar in magnitude, opposite in direction, and parallel to each other. These two forces are separated by a finite distance. In physics, the term moment also has the same meaning as torque. Torque is defined as the tendency of a force to rotate an object about an axis, a fulcrum, or a pivot. A torque can also be provided using a single force acting at a distance r from the axis of rotation. The torque of such a system is equal to the cross product of the applied force and r. Torque is mathematically defined as the rate change of angular momentum of an object. It can be clearly seen that this is compatible with the force – linear momentum relationship in linear movements. The torque is also equal to the product of the moment of inertia and the angular acceleration. Torque is a vector with the direction determined by the cross product of force and distance. It is perpendicular to the plane of rotation. Torque acting upon a fixed object creates torsion. Torque is also a common term used in motor mechanics. In that context, the torque of the engine resembles the acceleration capability of the vehicle.

What is Horsepower?

Horsepower is a unit used to measure power. The acronym used to denote horsepower is hp. The unit horsepower was originally created to compare the power of steamboats and draft horses. Even though the SI system is the standard measuring system in most countries, horsepower still is the most commonly used power unit in automobiles, electrical motors and many other mechanical appliances. The value of a horsepower can vary from 735.5 watt to 750 watt depending on the definition. One of the most important definitions of horsepower in automobile engineering is brake horsepower or bhp. Brake horsepower is the power of the engine without the gearbox and other equipment attached. Other forms of horsepower include metric horsepower, PS, CV, Boiler hp, electrical hp and many more. For engines, the power is equal to the product of torque and frequency of the engine multiplied by a constant depending on the units used.