What is the metric, that is SI, unit of force, and how is it defined in terms of mass and acceleration?

Question

Which of the following is not a unit of distance?

Answer 1

You can also arrive at the newton by starting from a real, everyday feeling of force and working backward through the formula.

Newton's second law tells us force equals mass multiplied by acceleration, \( F = ma \), so the unit of force must automatically come from multiplying the unit of mass by the unit of acceleration.
In the SI system, mass is measured in kilogram and acceleration is measured in metre per second squared, so multiplying these units together gives kilogram metre per second squared as the natural combined unit for force.
Rather than write out kilogram metre per second squared every time, scientists gave this combined unit a short name, the newton, in honour of Isaac Newton, who first stated the laws connecting force, mass, and acceleration.
So whenever a textbook says a force of, for example, 20 newton is applied, it really means a force that would give a 1 kilogram mass an acceleration of 20 metre per second squared, or equivalently a 20 kilogram mass an acceleration of 1 metre per second squared.

This confirms the newton as the metric SI unit of force, built directly from the base units kilogram, metre, and second.

Answer 2

You can also arrive at the newton by starting from a real, everyday feeling of force and working backward through the formula.

Newton's second law tells us force equals mass multiplied by acceleration, \( F = ma \), so the unit of force must automatically come from multiplying the unit of mass by the unit of acceleration.
In the SI system, mass is measured in kilogram and acceleration is measured in metre per second squared, so multiplying these units together gives kilogram metre per second squared as the natural combined unit for force.
Rather than write out kilogram metre per second squared every time, scientists gave this combined unit a short name, the newton, in honour of Isaac Newton, who first stated the laws connecting force, mass, and acceleration.
So whenever a textbook says a force of, for example, 20 newton is applied, it really means a force that would give a 1 kilogram mass an acceleration of 20 metre per second squared, or equivalently a 20 kilogram mass an acceleration of 1 metre per second squared.

This confirms the newton as the metric SI unit of force, built directly from the base units kilogram, metre, and second.

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