An object having the capability to do work is said to possess____________.
Energy
Understanding the Capability to Do Work
In physics, the term 'work' has a specific meaning. Work is done when a force causes a displacement of an object in the direction of the force. For work to be done, there must be a force applied, and the object must move as a result of that force.
The question asks what an object possesses if it has the capability to do work. This inherent ability is a fundamental property related to energy.
Analyzing the Options for Capability to Do Work
Let's examine each option provided:
- Inertia: Inertia is the property of an object that resists changes in its state of motion. An object with high inertia is hard to start moving or stop moving. Inertia is related to mass, not the ability to perform work. A stationary massive object has high inertia but cannot do work unless acted upon by an external force and moved.
- Force: Force is a push or pull that can cause a change in motion. While force is necessary to perform work (Work = Force × Displacement), having a force acting on an object doesn't automatically mean the object itself *possesses* the capability to do work on something else. For example, gravity exerts a force on an object, but the object's ability to do work is related to its position (potential energy) or motion (kinetic energy) because of that force field.
- Pressure: Pressure is force applied per unit area. It is relevant in fluid dynamics or when dealing with compressed gases, which can do work (e.g., expanding against a piston). However, pressure itself isn't the general capability to do work possessed by *any* object; it's a specific manifestation of force distribution, often related to stored internal energy in a system.
- Energy: Energy is defined precisely as the capacity or ability to do work. An object or system possesses energy if it can exert a force and cause displacement. This energy can take many forms, such as kinetic energy (energy of motion), potential energy (stored energy due to position or state), thermal energy, chemical energy, etc. When work is done, energy is transferred or transformed.
Comparing the Concepts
| Concept | Definition | Relation to Capability to Do Work |
|---|---|---|
| Inertia | Resistance to change in motion | Not directly related to the ability to do work. |
| Force | A push or pull | Required to do work, but not the inherent capability itself. |
| Pressure | Force per unit area | A specific form related to energy storage/transfer in certain systems, not the general capability. |
| Energy | The capacity to do work | This is the direct definition of what allows an object or system to do work. |
Conclusion on Possessing the Ability to Do Work
Based on the definitions in physics, the property an object possesses that gives it the capability to do work is energy. Whether an object is moving, is at a certain height, or has stored chemical bonds, it possesses energy, which is the measure of its potential to perform work on something else.
Revision Table: Key Physics Terms
| Term | Meaning | Unit (SI) |
|---|---|---|
| Work (W) | Force applied over a distance (W = Fd cosθ) | Joule (J) |
| Force (F) | A push or pull (F = ma) | Newton (N) |
| Energy (E) | The capacity to do work | Joule (J) |
| Inertia | Resistance to change in motion (related to mass) | Kilogram (kg) |
| Pressure (P) | Force per unit area (P = F/A) | Pascal (Pa) or N/m<sup>2</sup> |
Additional Information on Energy and Work
Energy exists in various forms, and it can be converted from one form to another. For example:
- A raised object has gravitational potential energy, which can be converted into kinetic energy and then used to do work (e.g., driving a pile into the ground).
- A moving object has kinetic energy, which can do work (e.g., colliding with another object and moving it).
- Chemical energy stored in fuel is converted into thermal energy and then mechanical energy in an engine to do work (e.g., moving a vehicle).
The total energy in an isolated system remains constant; it is only transformed or transferred. This is known as the law of conservation of energy. The ability to do work is directly linked to the presence and availability of energy in a system or object.
Important Questions from Work Power Energy
- Which of the following is a clear example of potential energy?
One erg is equal to ________ Joule.
An electric lamp of 100 W is used for 5 hours per day. How much energy will be consumed by the lamp for 3 days?
When you compress a spring you do work on it. The elastic potential energy of the spring:
If the velocity of a body is doubled its kinetic energy _______.
