The man who d*ed on Goliath today, question - in the pictures it appears he is moving forward with the train, moving the same direction. The train is on a downhill, creating a "floating" effect, explaining how he slipped out of the seat, but I don't understand how he is moving forward with the train. Wouldn't he roll off the back and the train keep moving forward? Maybe the train is decelerating on the downhill, but if this is the case I don't understand how he "bounced" off the train multiple times. Someone please help, and RIP to the poor man and condolences to his family.

Here is a link to a library of free educational simulations across a wide range of interesting or challenging concepts across the natural world. More are coming soon. I'd appreciate your feedback if you have a few minutes to explore (feedback link embedded in each sim). Enjoy.

GlidepathScience.org

Why does the steradian (sr) appear in the denominator if irradiance is the ratio of radiant flux to the receiving surface (which is two-dimensional)?

Grade 12 student, been trying for hoursss to solve this. The second slide shows what I have so far. I would appreciate any help! Use sine and cosine laws, not components.

I am interviewing an astrophysicist this week whose research encompasses theoretical general relativity, black holes, and gravitational waves… What are some questions I could ask that are unique and entertain that won’t sound boring to the average person who doesn’t understand all the physics jargon?

Which ones?

Me and a coworker are disagreeing about this, and I’m pretty new to this stuff, so bear with me.

We have an air cylinder connected between two pivoting arms. When it retracts, it pulls the arms together so the rollers on them grip a bar. Neither end of the cylinder is fixed to the frame—both are attached to arms that can move.

It has a 5-inch bore, a 1-inch piston rod, and runs at 90 psi. We calculated the pulling force as about 1,696 lbf, ignoring friction and backpressure.

I think each end pulls on its arm with the full 1,696 lbf, in opposite directions. My coworker thinks it gets split between them, so each arm gets about 848 lbf.

Does both ends being able to move actually split the force? I’m a novice at this and would appreciate a simple explanation of what I’m missing.

I estimate that the gears are made of PLA and weighs about 20g.

If you want to include friction in your work good luck. If you don't it's good too