Second law of motion
Newton’s second law of motion states:
The acceleration of an object is directly proportional to the net force acting on it, and inversely proportional to its mass.
What does this mean?
- If you apply a greater force to an object, it will accelerate more.
- If you apply the same force to a heavier object, it will accelerate less:
- That’s because heavier objects need more force to accelerate them (because they have more inertia).
Equations
In short, Newton’s second law of motion can be written as:
Where:
\Sigma F is the net (resultant) force acting on the object in newtons (N )m is the mass of the object in kilograms (kg )a is the acceleration of the object in meters per second squared (ms^{-2} )
flashcards
| Question | Answer |
|---|---|
| Newton’s second law of motion states that acceleration is directly proportional to what, and inversely proportional to what? | Acceleration is directly proportional to the net force acting on an object, and inversely proportional to its mass. |
| What is the equation that summarizes Newton’s second law of motion? | |
| In the equation | |
| In the equation | |
| In the equation | |
| If you apply a greater force to an object, what happens to its acceleration according to the second law? | It will accelerate more (acceleration is directly proportional to net force). |
| If you apply the same force to a heavier object, what happens to its acceleration? | It will accelerate less (acceleration is inversely proportional to mass). |
| Why do heavier objects need more force to accelerate them at the same rate as lighter objects? | Because heavier objects have more inertia. |