Virtual Clicker https://pollev.com/dannycaballe980 Notes for today http://dannycaballero.info/phy482msu_s2020/notes/31-slides.html

## Changes to Syllabus * Pair project is cancelled. One additional homework problem per week. * Homework: 40% -> 50% * Individual Project: 20% -> 25% * Quizzes: 20% -> 25% Will still drop one homework assignment and quiz. I will take into account the wildly-extenuated circumstances when assigning letter grades.

## Demo [Galilean relativity example courtesy of Jamiroquai](https://www.youtube.com/watch?v=4JkIs37a2JE)

Standing on a moving walkway in the airport that is moving at 1 m/s to the right, you toss a ball into the air. You observe the ball moving straight up and down. I'm sitting on a bench watching your shenanigans. What do I have to do to make my physics match yours? That is, what do I have to do to reproduce all your measurements? 1. Add 1 m/s to the left 2. Add 1 m/s to the right 3. Subtract 1 m/s to the right 4. Subtract 1 m/s to the left 5. None or more than one of these Note: * Correct Answer: E (it's A and C)

A rocket is moving to the right at speed $v = (3/4)c$, relative to Earth. On the front of the rocket is a headlight which emits a flash of light. <img src="./images/rocket_light.png" align="center" style="width: 700px";/> In the reference frame of a passenger on the rocket, the speed of the light flash is 1. $c$ 2. 7/4 $c$ 3. 1/4 $c$ 4. None of these Note: * Correct Answer: A

A rocket is moving to the right at speed $v = (3/4)c$, relative to Earth. On the front of the rocket is a headlight which emits a flash of light. <img src="./images/rocket_light.png" align="center" style="width: 700px";/> According to a person at rest on the earth, the speed of the light flash is 1. $c$ 2. 7/4 $c$ 3. 1/4 $c$ 4. None of these Note: * Correct Answer: A

A rocket is moving to the right at speed $v = (3/4)c$, relative to Earth. On the front of the rocket is a headlight which emits a flash of light. <img src="./images/rocket_light.png" align="center" style="width: 700px";/> According to a person moving toward the rocket at speed $(3/4)c$, relative to earth, the speed of the light flash is 1. $c$ 2. 7/4 $c$ 3. 1/4 $c$ 4. None of these Note: * Correct Answer: A

Consider a $S'$ frame moving with a speed $v$ in 1D with respect to a stationary frame $S$. Using your everyday intuition, write down the relationship between a position measurement $x$ and $x'$. *Be ready to explain why this makes sense to you.* Note: This is just to get them thinking about the Galilean transformation again as you will do this with gamma.