# The Boat/Rock Brainteaser ft Simone Giertz part 2/3 | Summary and Q&A

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February 2, 2017
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Physics Girl
The Boat/Rock Brainteaser ft Simone Giertz part 2/3

## TL;DR

Dianna and Simone discuss the concept of air resistance and how it affects objects of different weights falling at terminal velocity, as well as the function of transistors.

## Key Insights

• 👱 Air resistance depends on the shape and surface area of an object, not its weight.
• 👱 Terminal velocity is the constant speed at which an object falls when gravity and air resistance balance each other.
• ✋ Heavier objects require a higher force to slow down their acceleration and reach a higher terminal velocity.
• 💐 Transistors are electronic devices that control the flow of current and voltage in electronic circuits.
• 🎮 Transistors act as control valves, allowing small signals to control larger currents.
• 👱 Understanding air resistance and terminal velocity is crucial in fields like physics, engineering, and aerodynamics.
• 🖐️ Transistors play a vital role in electronic devices and circuit design.

## Transcript

Hi, I'm Dianna. You're watching Physics Girl. And welcome to Part 2 of physics riddles with my friend, Simone Giertz. If you haven't seen the first part, there is a warmup question I asked Simone and an introduction to who she is. There's a link in the description. There's a card somewhere. So here's a recap of the first riddle and the answer. You... Read More

### Q: Why do two spheres of the same size but different weights experience the same air resistance at terminal velocity?

Air resistance is determined by the shape and surface area of an object, not its weight. As long as the two spheres have the same shape and surface, they will experience the same air resistance when falling at terminal velocity.

### Q: What is terminal velocity?

Terminal velocity is the constant speed at which an object falls when the force of gravity pulling it down is equal to the force of air resistance pushing it up. At terminal velocity, there is no change in velocity, and the object stops accelerating.

### Q: Why does the heavier iron ball reach a higher terminal velocity than the lighter wood ball?

The heavier ball requires a higher force to slow down its acceleration because it has more gravitational pull. It takes the air longer to counteract the force of gravity on the heavier ball, resulting in a higher terminal velocity.

### Q: What is the function of a transistor?

A transistor is an electronic device that can amplify or switch electronic signals and electrical power. It acts as a control valve, allowing a small voltage to control a larger current.

## Summary & Key Takeaways

• Dianna and Simone discuss the first riddle about two spheres of different weights experiencing the same air resistance at terminal velocity.

• They explain that air resistance is proportional to velocity squared and discuss how the force of gravity affects terminal velocity.

• The second part of the video involves Dianna asking Simone engineering questions, including the function of transistors.