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IAL M2-Work & Energy
Work, Energy & Momentum
Interactive Learning Notes for Mechanics
1. Work and Energy
Work Done
Work is done when a force moves its point of application. It's energy transfer.
General Formula: Work = Force × Distance (in direction of force)
Work Against Gravity: Work = mgh
m = mass (kg)
g = 9.8 m/s²
h = vertical height (m)
Interactive Example: Work Calculation
Kinetic Energy (K.E.)
Energy due to motion
K.E. = ½mv²
K.E. Calculator
Potential Energy (P.E.)
Energy due to position in gravitational field
P.E. = mgh
Remember to choose a zero level for P.E. reference
2. Conservation of Mechanical Energy
Principle
When only gravity does work (no friction/resistance):
Initial (K.E. + P.E.) = Final (K.E. + P.E.)
Work-Energy Principle
When other forces do work:
Work Done = Change in Kinetic Energy = ½mv² - ½mu²
Sliding Block Simulation
3. Power
Definition
Power is the rate of doing work
Power = Work Done / Time Taken
Power = Force × Velocity (for moving vehicles)
Power Calculator
4. Momentum and Impulse
Momentum
Momentum = mass × velocity (p = mv)
Impulse
Impulse = Force × time = Change in momentum (I = mv - mu)
Conservation of Momentum
In a closed system with no external forces:
m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂
Collision Calculator
Particle A
Particle B
5. Newton's Law of Restitution
The Law
Speed of Separation = e × Speed of Approach
e = coefficient of restitution
0 ≤ e ≤ 1
- e = 1: Perfectly elastic (K.E. conserved)
- e = 0: Perfectly inelastic (objects stick together)
Bouncing Ball
Key Formulas Summary
Work = F × s
Work vs. Gravity = mgh
K.E. = ½mv²
P.E. = mgh
Power = F × v
Momentum = mv
Impulse = mv - mu
Separation = e × Approach