For Class 8, 9 & 10
Foundation - a strong base in Physics, Chemistry, Maths & Biology
Concept-first questions with clear model answers across all four subjects, aligned to NCERT. Start early, build the habit, and walk into your board exams, NEET and JEE already ahead.
Showing 1 question in Physics for Class 9. Tap a card to reveal the answer.
PhysicsForce and Laws of MotionmediumState Newton's second law of motion and define momentum.
Reveal answer ↓
What it is
Force is what changes an object's momentum; for a fixed mass, force = mass x acceleration.
Answer
Newton's second law states that the rate of change of momentum of a body is directly proportional to the applied force and takes place in the direction of the force; for constant mass this gives F = ma. Momentum is the quantity of motion of a body, equal to the product of its mass and velocity, p = mv.
F = ma ; p = mv
- •Rate of change of momentum is proportional to force
- •F = ma (for constant mass)
- •Momentum p = mv
- •Change is in the direction of the force
Why learn this
It's why seatbelts and airbags save lives, and how rockets and cricket shots are designed.
💡 Memory trick
F = ma ('Force = Mass Accelerates'); momentum p = mv is 'mass in motion'.