Which is a correct statement about mechanical power?
A It is a vector quantity - AQA - A-Level Physics - Question 18 - 2019 - Paper 1
Question 18
Which is a correct statement about mechanical power?
A It is a vector quantity.
B It is measured in J.
C In fundamental units, its unit is kg m² s⁻³.
D It can be... show full transcript
Worked Solution & Example Answer:Which is a correct statement about mechanical power?
A It is a vector quantity - AQA - A-Level Physics - Question 18 - 2019 - Paper 1
Step 1
A It is a vector quantity.
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Answer
This statement is incorrect. Mechanical power is a scalar quantity, as it does not have a direction associated with it.
Step 2
B It is measured in J.
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Answer
This statement is also incorrect. While mechanical energy is measured in joules (J), power is measured in watts (W), which is equivalent to joules per second (J/s).
Step 3
C In fundamental units, its unit is kg m² s⁻³.
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Answer
This statement is correct. The fundamental unit of power, the watt, can be expressed in fundamental SI units as kg m² s⁻³.
Step 4
D It can be calculated from force × distance moved.
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Answer
This statement is misleading. While work can be calculated as force multiplied by distance, power involves the rate at which work is done, so it should be expressed as work done per unit time.
