If a force applied to an object does not change with respect to time, it is known as a constant force. A constant force helps to maintain the constant speed of an object and allows an object to exhibit uniform motion. Similarly, a force applied to a stationary object is said to be constant if it helps to maintain its state of equilibrium. In other words, a force that tends to act on an object for an infinitely long amount of time, provided the physical conditions remain the same, is known as a constant force.
Examples of Constant Force
All the objects present on the surface of the earth experience a pull towards the core known as the gravitational force. The magnitude/the intensity with which the object is attracted to the earth contributes to the weight of that particular object. The weight remains unaffected by the variation in time, i.e., it is constant. In other words, gravity acts on an object irrespective of the change in time, which is why it is listed under the category of constant forces.
2. Force of Friction
The force of friction is offered in response to the motion of an object. It tends to oppose the movement of that particular body. Friction offered to an object does not depend on the time. The intensity of friction is maintained to a specific value at every instant of time. Hence, the force of friction is a prominent example of constant force.
Upthrust or buoyant force is the force exerted by a fluid on a body that comes in contact with it. For instance, the force offered by the water to the surface of the boat is evenly distributed and does not depend on time. The object placed in fluid experiences the effect of buoyancy as long as it maintains contact with the fluid; moreover, there exists no change in the intensity of the force exerted by it. Hence, upthrust is a constant force.
A pendulum exhibits a to and fro motion continuously till the energy contained by it dies out. To sustain the continuous movement of a pendulum, it must be supplied with a constant force. This constant force can be provided by pushing the pendulum or by creating an artificial set-up.
5. Holding an Object
The work done by holding an object in a stationary position is equal to zero because no displacement takes place; however, it requires a considerable amount of force to maintain the stationary position of the object. This force is required to be constant in nature; otherwise, the object tends to lose its state of rest and starts to exhibit motion.
Cycling is one of the best examples that demonstrate the existence of a constant force. To keep a bicycle into motion it is required to be supplied with a significant amount of mechanical force. To maintain the persistent speed of the bicycle, it has to be provided with a force that remains the same and does not change with change in time and distance; therefore, the force that keeps the bicycle moving at the same speed throughout the journey is known as a constant force.
7. Hydrostatic Force
Hydrostatic force is the force exerted by a fluid on the exterior of a body submerged into it. It tends to act on the object as long as the object is suspended in the fluid. It does not depend on the time variation, which is why it is continuous in nature. Hence, hydrostatic force is a constant force.
8. Intermolecular/Intramolecular Force
The force existing between the molecules of a compound or between the molecules of two different compounds is known as intermolecular force and intramolecular force, respectively. These forces tend to maintain the stability of the compounds. Such forces do not fade away or grow strong with time. This invariability with respect to time leads to the listing of both the forces under the category of constant force.