Measuring Force
Force is measured in newton, symbol N, which is the SI unit of force.
In one line: Force unit is N because Newton's law gives F = ma.
Practice This ConceptUnderstand it
A force can be compared by the change it produces in motion or shape. In school physics, one newton is the force that gives a mass of 1 kg an acceleration of 1 m/s².
Example
Rule to remember
F = ma; F is force in newton, m is mass in kilogram, and a is acceleration in m/s².
See it worked out
Follow the example line by line, then use the same method on new questions.
Worked example
For m = 4 kg and a = 2 m/s², F = ma = 4 × 2 = 8 N.
Method you can reuse
Visual tip
A labelled block with a force arrow and acceleration arrow in the same direction can support numerical questions.
Check yourself
Answer the question in your head before opening the answer.
Try it yourself
Why is newton used instead of kilogram for force?
Think first, then show answerHide answer
Common wrong answer
Writing 8 kg instead of 8 N.
Why it loses marks: The calculated quantity is force, not mass.
Don't mix this up
Exam tip
Write it in the exam
Each point is worth about one mark. Write point 1 for a 1-mark question and keep adding points as the marks go up.
How CBSE asks it
- 1
Enough for 1 mark
Force is measured in newton, symbol N, which is the SI unit of force.
- 2
Add for 2 marks
Example: If a 2 kg object accelerates at 3 m/s², the force on it is 6 N using F = ma.
- 3
Add for 3 marks
A force can be compared by the change it produces in motion or shape.
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