The velocity of hail is greater than that of a water drop mainly due to differences in mass, size, and air resistance.
Key Reasons:
- Greater Mass of Hail:
- Hailstones are heavier and denser than water droplets
- Greater mass means higher gravitational force (weight) acting downward
- Effect of Air Resistance:
- Air resistance (drag) opposes motion
- For heavier objects like hail, the effect of air resistance is relatively smaller compared to their weight
- For lighter water droplets, drag significantly slows them down
- Higher Terminal Velocity:
- Hail reaches a higher terminal velocity than water drops
- Water drops are lighter and reach lower terminal velocity quickly
Concept: Terminal Velocity
Terminal velocity is the constant speed reached when gravitational force = air resistance
- Hail → higher terminal velocity
- Water drops → lower terminal velocity
Key Takeaway:
Hail falls faster than water droplets because it has greater mass and experiences relatively less effect of air resistance, resulting in a higher terminal velocity.