Join 60,000+ competitive exam aspirants
Which of the following is a scalar quantity in physics?
Velocity
Force
Work
Acceleration
Work
Work is a scalar quantity because it is defined as the dot product of two vectors, force and displacement, resulting in a single magnitude without a specific direction. While it involves vector inputs, the resulting scalar value represents the energy transferred to or from an object.
Work is a scalar quantity because it is defined as the dot product of two vectors, force and displacement, resulting in a single magnitude without a specific direction. While it involves vector inputs, the resulting scalar value represents the energy transferred to or from an object.
If you lift a box, you exert force in a direction, but the 'work' done is just the energy amount measured in JoulesтАФmuch like how a shopping bill shows the total cost without indicating which direction you carried the items.
TV-FAS (Think: Time, Volume, Force, Acceleration, Speed - wait, remember 'Scalar' includes 'Work', 'Energy', 'Power' which are 'SWEP').
W=FтЛЕd тАФ Definition of work as a scalar dot product of force and displacement
W=Fdcos(╬╕) тАФ Scalar calculation of work using the angle ╬╕ between force and displacement
Work is calculated using the formula W=FтЛЕd=Fdcos(╬╕), where F is the force vector and d is the displacement vector. Since the dot product of two vectors produces a scalar value, work only possesses magnitude and no direction.
Scalar quantities only possess magnitude.
Vector quantities possess both magnitude and direction.
The dot product of two vectors always yields a scalar.
Work can be positive, negative, or zero depending on the angle ╬╕.
Simplifies physical calculations by removing directional dependency in energy transfer problems.
Calculation of energy expenditure in mechanical systems.
Thermodynamic studies involving expansion or compression of gases.
| Feature | Vector Quantities | Scalar Quantities |
|---|---|---|
Quantity Type | Vector (Velocity, Force, Acceleration) | Scalar (Work) |
The SI unit of work is the Joule (J), equivalent to 1┬аNтЛЕm or 1┬аkgтЛЕm2/s2.
Velocity, Force, and Acceleration are vector quantities as they require both magnitude and direction to be fully defined.
C is correct тАФ Work is defined as the dot product of force and displacement vectors, which results in a scalar quantity.
Always remember that any physical quantity derived from a dot product of two vectors is a scalar (e.g., Work, Power, Magnetic Flux).