Discover how F = ma is derived from momentum principles and solve real-world problems using Newton's equations
5kg
u = 3 m/s
→ F
t = 0t = 2s
Initial Momentum:
p₁ = mu = 5 × 3 = 15 kg⋅m/s
Final Momentum:
p₂ = mv = 5 × 7 = 35 kg⋅m/s
Change in Momentum:
Δp = mv - mu = 35 - 15 = 20 kg⋅m/s
Rate of Change (Force):
F = Δp/t = 20/2 = 10 N
Since a = (v - u)/t = (7-3)/2 = 2 m/s²:
F = ma = 5 × 2 = 10 N ✓
🏏
Cricket Fielder Catching
A fielder pulls hands backward while catching to increase the time (t) over which
the ball's momentum changes. This reduces the force F = Δp/t on the hands.
↑ time → ↓ force → less pain!
🤸
High Jump Landing
Athletes land on cushioned beds or sand to increase the stopping time.
This decreases the rate of momentum change and reduces impact force.
Soft landing → ↑ t → ↓ F
🥋
Karate Ice Break
A karate player delivers maximum momentum change in minimum time by
striking swiftly. Very short contact time creates enormous force.
↓ time → ↑ force → break!
Explore F = ma
Newton's Second Law - Mathematical Form
F = ma
Force equals mass times acceleration. This fundamental equation relates the force applied
to an object with its mass and the resulting acceleration.
📏 Units and Definitions
Force (F): Newton (N) = kg⋅m/s² Mass (m): kilogram (kg) Acceleration (a): meter per second squared (m/s²)
Definition: One Newton is the force required to accelerate a 1 kg mass at 1 m/s²