- 2078 Kartik · 2 marks
Work-energy vs impulse-momentum principles
Short answer
Work–energy is a scalar principle relating net work to change in kinetic energy, integrated over displacement. Impulse–momentum is a vector principle relating impulse to change in linear momentum, integrated over time. Work–energy is ideal for problems involving forces acting over distances; impulse–momentum suits impacts and short-duration forces.
Differentiate the concept of "work-energy" and "impulse-momentum" principles for study of kinetics of particle.
| Point | Work-energy principle | Impulse-momentum principle |
|---|---|---|
| Statement | Work done by all forces = change in kinetic energy | Impulse of all forces = change in linear momentum |
| Equation | ||
| Quantity | Scalar | Vector (components needed) |
| Force integrated over | Displacement (position) | Time |
| Best used when | Forces and distances are known (springs, gravity, friction over a path) | Forces and times are known, or in impact and short-duration forces |
| Unknowns found | Speed (direction is not given) | Velocity with direction; also impulsive forces |
| Internal/normal forces | Normal force that does no work is ignored | All forces including normal reactions must be included |
✓ Answer checked by Claude Opus 5.5 (high effort)
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