How fast does the average raindrop fall? Snowflake? Large hailstone?

Question

How fast does the average raindrop fall? Snowflake? Large hailstone?

Answer 1

Raindrop = 7 mph.

Answer 2

rain falls at 7 mph.

Answer 3

The rate of acceleration due to gravity...the same speed that everything falls at.

I believe it's 9.8 meters per second squared (9.8 m/s^2).

Answer 4

Can information be both tedius and interesting?

The following is:

It depends on the size and weight of the raindrop how fast it falls: the heavier, the faster.

At sea level, a large raindrop about 5 millimeters across (house-fly size) falls at the rate of 9 meters per second (20 miles per hour).

Drizzle drops (less than 0.5 mm across, i.e., salt-grain size) fall at 2 meters per second (4.5 mph).

A raindrop starts falling and then picks up speed because of gravity.

Simultaneously, the drag of the surrounding air slows the drop's fall. The two forces balance when the air resistance just equals the weight of the raindrop.

Then the drop reaches its terminal velocity and falls at that speed until it hits the ground.

This simple view neglects updrafts, downdrafts, and other complications.

The air resistance depends on the shape of the raindrop, the cross-sectional area presented to the airflow, and the raindrop's speed.

Most drops are fairly round — the small ones spherical, larger ones flattened on the bottom by the airflow.

At high speeds, the air resistance increases with the square of the velocity.

http://www.wonderquest.com/falling-raind...

The average snowflake falls at a speed of 3.1 miles per hour. (5 kilometers)

http://www.suite101.com/article.cfm/scie...

Hail can falls much faster, because its diameter can be larger.

Its fallspeed is approximately given by 1.4 D0.8 at sea level, the exact relationship depends on hail density and shape.

For instance, a large hailstone of 8 cm (D=80 mm) weighs about 0.7 kg and falls at 48 m/s!

Research has found that a hailstone's terminal velocity is roughly proportional to the square root of its diameter, with a diameter of 1 cm corresponding to a terminal velocity of 50 km/h

"Hailstones can reach a speed of 90 mph (140 km hr–1) as they fall to the ground!"

More way-cool facts about hailstones at:

http://hypertextbook.com/facts/2005/Alic...

By the way freesumpin', a falling human hurtles to the ground at a terminal velocity of about 125 miles per hour.

Hmmm, what do you weigh?