Interactive physics simulator
Newton's Second Law of Motion: F = ma
Newton's Second Law explains how net force, mass, and acceleration are connected. Greater net force gives greater acceleration, while greater mass gives smaller acceleration for the same force.
Newton's Second Law Simulator
Change net force and mass to see acceleration update live through F = ma.
Live Result
- Net Force
- 40 N
- Mass
- 10 kg
- Acceleration
- 4 m/s²
- Velocity
- 0 m/s
- Distance
- 0 m
- Formula
- a = F / m
What is Newton's Second Law of Motion?
Newton's Second Law of Motion says that acceleration depends on net force and mass. For the same mass, a larger net force gives a larger acceleration. For the same net force, a larger mass gives a smaller acceleration.
The law is written as F = ma. The force in this equation is the net force, not just one push or pull.
Key Definition
Newton's Second Law connects net force, mass, and acceleration.
- Greater net force causes greater acceleration.
- Greater mass causes smaller acceleration for the same force.
- Acceleration points in the direction of the net force.
- If net force is zero, acceleration is zero.
- Mass measures resistance to acceleration.
Newton's Second Law Formula
F = ma
a = F / m
m = F / a
- F = net force in newtons (N)
- m = mass in kilograms (kg)
- a = acceleration in m/s2
Force, Mass and Acceleration
| Change | Result | Reason |
|---|---|---|
| Force increases | Acceleration increases | a = F / m |
| Mass increases | Acceleration decreases | More inertia |
| Net force is zero | Acceleration is zero | F = ma |
Real-life Example
A rocket sled with small mass accelerates quickly when a strong net force acts on it. A heavier sled pushed by the same force accelerates more slowly.
- Same mass + bigger force = bigger acceleration.
- Same force + bigger mass = smaller acceleration.
- The direction of acceleration matches the net force.
Solved Examples
A 4 kg lab capsule is pushed by a net force of 20 N. Find its acceleration.
- Use F = ma.
- Rearrange to a = F / m.
- a = 20 / 4 = 5 m/s2.
Answer: 5 m/s2
A drone of mass 2 kg accelerates at 6 m/s². Find the net force.
- Use F = ma.
- F = 2 × 6.
- F = 12 N.
Answer: 12 N
A 60 N net force gives an object acceleration of 3 m/s². Find its mass.
- Use F = ma.
- Rearrange to m = F / a.
- m = 60 / 3 = 20 kg.
Answer: 20 kg
Common Mistakes
- Using one force instead of net force.
- Forgetting mass must be in kilograms.
- Forgetting acceleration uses m/s2.
- Thinking heavier objects always have more acceleration.
- Forgetting direction of force matters.
- Confusing mass with weight.
Quick Summary
- Newton's Second Law is F = ma.
- It uses net force.
- Acceleration equals force divided by mass.
- Force is measured in newtons.
- Mass is measured in kilograms.
- Acceleration is measured in m/s2.
Practice Questions
1. A 5 kg object has a net force of 25 N. Find acceleration.
a = F / m = 25 / 5 = 5 m/s2.
2. A 3 kg drone accelerates at 4 m/s². Find net force.
F = ma = 3 × 4 = 12 N.
3. A net force of 80 N gives acceleration 4 m/s². Find mass.
m = F / a = 80 / 4 = 20 kg.
4. If mass stays the same and net force doubles, what happens to acceleration?
Acceleration doubles.
5. If net force stays the same and mass doubles, what happens to acceleration?
Acceleration becomes half.
6. Does F = ma use balanced force or net force?
It uses net force, the total unbalanced force on the object.
FAQ
Frequently Asked Questions
What is Newton's Second Law of Motion?
Newton's Second Law states that the net force on an object equals mass multiplied by acceleration: F = ma.
What is the formula for Newton's Second Law?
The formula is F = ma, where F is net force, m is mass, and a is acceleration.
Does F = ma use total force or net force?
F = ma uses net force, meaning the overall unbalanced force after all forces are combined.
What is the SI unit of force?
The SI unit of force is the newton, written as N. One newton equals 1 kg m/s².
How do you find acceleration from F = ma?
Rearrange the formula to a = F / m. Acceleration equals net force divided by mass.
How do you find mass from F = ma?
Rearrange the formula to m = F / a, as long as acceleration is not zero.
What happens if force increases but mass stays the same?
Acceleration increases in direct proportion to net force.
What happens if mass increases but force stays the same?
Acceleration decreases because the same force must accelerate more mass.
Can acceleration be zero in Newton's Second Law?
Yes. If net force is zero, then acceleration is zero.
Why is mass important in Newton's Second Law?
Mass measures inertia. A larger mass resists changes in motion more, so it accelerates less for the same net force.
How does the simulator calculate acceleration?
The simulator calculates acceleration using a = F / m and updates velocity and distance as the object moves.
Is force a vector?
Yes. Force has magnitude and direction, and acceleration points in the direction of the net force.