Raindrops Sliding Down Car Window: Speed?

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SUMMARY

The discussion centers on the dynamics of raindrops sliding down a car window at an angle of approximately 45 degrees during rainfall. It establishes that the balance between wind force and gravitational force influences the behavior of the raindrops. However, to accurately calculate the speed of the car, one must also consider the adhesive force holding the drops to the window, which affects friction. Additionally, the size and shape of the raindrops play a significant role in determining wind drag but do not impact gravitational force.

PREREQUISITES
  • Understanding of basic physics principles, specifically forces and motion.
  • Knowledge of friction and its effects on moving objects.
  • Familiarity with fluid dynamics, particularly regarding raindrop behavior.
  • Awareness of how wind drag influences object movement.
NEXT STEPS
  • Research the principles of fluid dynamics related to raindrop behavior on surfaces.
  • Study the effects of friction on moving objects in various environments.
  • Learn about the calculations involved in determining wind drag on different shapes.
  • Explore the relationship between gravitational force and adhesive forces in physics.
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Physics students, automotive engineers, meteorologists, and anyone interested in the dynamics of raindrops and vehicle motion.

daniel_i_l
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I was in a car on a rainy day and saw that the drops on the window were sliding down the window at about 45 deg. , I guess that that means that the force of the wind on the raindrops is about equal to the gravitational force but is that enough to calculate the speed of the car?
 
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Unfortunately, no: you need to know the force holding the drops to the window.
 
russ_watters said:
Unfortunately, no: you need to know the force holding the drops to the window.
Yes. That would affect friction. Friction alters wind drag but not gravity. Same with size/shape of raindrops. Will affect wind drag, but not gravity.
 

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