Force and Momentum: Definitions, Formulas, and Easy Examples
FAQs on What Is the Difference Between Force and Momentum?
1. What is the difference between force and momentum?
Force is a push or pull that changes an object’s state of motion, while momentum is the quantity of motion possessed by a moving object.
Key differences include:
- Force is an external cause influencing motion (measured in newtons, N).
- Momentum is a property of a moving body (measured in kg·m/s).
- Force changes momentum over time (F = rate of change of momentum).
- Momentum depends on mass and velocity (p = m × v).
2. Define force with an example.
Force is a physical quantity that can change the state of rest or motion of an object.
For example:
- Pushing a stalled car applies force to make it move.
- Lifting a book from a table requires force.
3. How do you calculate momentum?
Momentum is calculated by multiplying an object’s mass by its velocity.
The formula is: Momentum (p) = mass (m) × velocity (v)
- Mass is measured in kilograms (kg).
- Velocity is measured in metres per second (m/s).
- The SI unit of momentum is kg·m/s.
4. How are force and momentum related?
Force and momentum are related through Newton’s Second Law of Motion.
- Force equals the rate of change of momentum (F = Δp/Δt).
- If a constant force acts on an object, it changes the object’s momentum over time.
- This relationship links the concepts of force, mass, velocity, and acceleration.
5. List two differences between force and momentum.
Force and momentum differ in their definition and physical significance.
Differences include:
- Force is an action that initiates a change in motion; momentum is a property indicating the amount of motion.
- Force is measured in newtons (N); momentum in kg·m/s.
6. What is the SI unit of force and momentum?
The SI unit of force is newton (N), and the SI unit of momentum is kilogram metre per second (kg·m/s).
- 1 newton = 1 kg·m/s² (for force)
- 1 kilogram metre per second = 1 kg·m/s (for momentum)
7. Can an object have momentum without force acting on it?
Yes, an object can have momentum without a force acting on it if it moves with constant velocity.
- Momentum is present as long as there is motion (p = m × v).
- Force is only needed when changing the object’s speed or direction.
8. Is force a scalar or vector quantity? What about momentum?
Both force and momentum are vector quantities.
- They each have both magnitude and direction.
- This property is important in predicting and analyzing motion in physics problems.
9. Why is momentum important in physics?
Momentum is essential because it quantifies the motion of objects and is conserved in isolated systems.
- It helps explain situations like collisions and explosions.
- Conservation of momentum is a key law in the CBSE physics syllabus.
- It allows prediction of motion after interacting with other objects.
10. Give one real-life example each for force and momentum.
Force Example: Pushing a shopping cart to move it forward.
Momentum Example: A moving football has momentum; when it hits the goalpost, it can rebound due to its momentum.
These examples help connect textbook definitions to daily experiences and exam situations.






















