Driving force is the force that is responsible to put an object into motion. In the absence of the driving force, an object is not able to change its shape, state, size, or position. The driving force is also known as the external force. Whenever there exists a driving force in action, an opposing force, known as a retarding force, is also present. The main task of a retarding force is to oppose the motion of the object or slow down the speed with which it is moving. If the magnitude of the driving force is greater than the retarding force, the object speeds up. If the value of the driving force is less than the retarding force, the object slows down. If both the forces are equal in magnitude, then there exists no change in the state, shape, or position of the object. This is because both the forces acting from opposite directions with equal magnitude establish a condition of equilibrium and forbid any motion.
Examples
1. Using Sound to Break a Glass
When a glass is subjected to high-frequency sound waves, it tends to develop certain cracks. On increasing the frequency of the sound wave, it might shatter into pieces. The sound energy causes a certain amount of deformation and damage to the structure of the glass. Therefore, here, sound acts as a driving force.
2. Pendulum Action
A pendulum is put into motion with the help of a mechanical force. In the equilibrium condition, the pendulum hangs to the hook and does not move. The tension force possessed by the string, with which the pendulum is tied, and the mechanical force that supplies energy to the hanging mechanism of the pendulum, are the driving forces responsible to keep a pendulum in motion.
3. Free-falling Objects
An object freely falling towards the ground is pulled towards the center of the earth’s core due to the gravitational force in action. Here, gravity is accountable to put the objects into motion. Therefore, in the case of a freely falling object, the force of gravitation acts as a driving force.
4. Spinning a Top
To spin a top, it has to be supplied with a significant amount of rotational force. The rotating force sets the top to move in a circular direction about its axis. Without the application of the rotating force, the top cannot be put into motion. Therefore, the rotating force here acts as the driving force. A force of friction acts in the direction opposite to the driving force that tends to slow down the speed of the spinning top.
5. Driving a Car
To provide acceleration to a car, the engine of the car is required to be ignited. The engine of the car then is able to develop the necessary driving force to put the vehicle into motion. When the ignition system or the driving force is cut off, the vehicle comes to rest.
6. Merry-Go-Round
The swings attached to the rotating roof of a merry-go-round ride tend to move towards the outer side. The force that compels the swings to leave their state of equilibrium and get dislocated from their original position is the centrifugal force. The centrifugal force is a pull force applied to every rotating object in nature. This force, here, is regarded as a driving force.
7. Winding a Toy
There are certain toys in the market, which are operated with the help of the mechanical force stored with the help of winding a key. The key is rotated multiple times in a particular direction. This helps to store a considerable amount of energy in it. When the key is released, the toy exhibits motion. Hence, this stored mechanical force, here, acts as a driving force to the toy.
8. Dragging a Strolly
When a strolly is dragged, it is set to motion. The motion takes place as long as the pull force is applied to the suitcase. This means that the pull force supplied by the user is responsible to drive the suitcase. Hence, this force required to pull or drag the suitcase is known as a driving force.
9. Twisting a Screw
To fix or embed a screw into a rigid wall or a wooden plank, the tip of the screw is placed on the surface, and the top of the screw is made to rotate in a particular direction. This helps the thread cuttings on the screw to form grooving into the structure as per requirement. The force that gets developed due to the turning of the screw is called the twisting force. The twist or the torsion force sets the screw into motion. Hence, it is known as the driving force.
10. Nail Attracted towards Magnet
When an iron nail is placed in close proximity to a magnet, it experiences a strong force of attraction. This force of attraction pulls the nail towards the magnetic body. The force is said to be a non-contact force because the motion of the nail occurs indirectly without any physical contact of both bodies. The magnetic force, here, is responsible to put the nail into motion and is regarded as the driving force.