Concept explainers
The metric unit of a joule (J) is a unit of _
a. potential energy.
b. work.
c. kinetic energy.
d. any of the above.
The parameter which has unit of Joule, from the following options.
Potential energy
Work
Kinetic energy
Any of the above
Answer to Problem 2AC
Solution:
Option (d) is correct.
Explanation of Solution
Introduction:
According to the concept of mechanical work, net work is done by an external force, if there is a net displacement in the same direction in which the force is applied.
Mathematically, work can be defined as:
Here,
The metric unit for Work is
The kinetic energy of a body is the energy possessed by a body due to its motion. Example: Energy by a moving car, flowing water.
Mathematically, it is expressed as:
Here,
The potential energy of a body is the energy possessed by a body due to its relative position. Ex: A car on a high mountain possesses potential energy due to the suitable height from the ground level.
Mathematically, it is expressed as:
Here,
Explanation:
Reason for the correct option:
The unit for kinetic energy can be derived as follows:
Consider mass
Substitute
Hence, Joule is a unit for kinetic energy.
Consider the expression for work.
Consider the force as
Substitute
Hence, Joule is a unit for work.
The unit for potential energy can be derived by
Since
Joule is also the unit for potential energy.
So all options (a), (b) and (c) are true therefore option (d) is the correct choice.
Hence, option (d) is correct.
Justify reasons for the incorrect statements:
Since all options (a), (b) and (c) are true therefore option (d) is the correct choice.
Hence, option (a), (b) and (c)are incorrect choice.
Conclusion:
Joule is unit for Work, Kinetic energy and Potential Energy.
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Chapter 3 Solutions
Physical Science
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