Mythbusters - Soccer Ball Shot from Truck
Why Physics Stack Exchange recommends it
Physics Stack Exchange answerers and commenters link it as a quick, concrete demonstration of Galilean relativity whenever someone asks about projectiles fired from, or thrown inside, a moving vehicle.
Recommended by 1 people across 1 different months, 2013 to 2019.
What it is
A one-minute MythBusters clip, reposted by physics teacher Frank Noschese, in which a soccer ball is fired backwards from a pickup truck at the same speed the truck is moving forward. To a stationary observer the ball drops straight down, illustrating how velocities add between reference frames.
What people said
Recommends stafusa · 2018-07 · Physics Stack Exchange · on “Why does bullet falls on the earth if shooter moving back at same speed of firing?”
Velocities are added and $v+(-v)=0$. Check for Galilean transformation [LINK] . You'll also probably enjoy the video Mythbusters - Soccer Ball Shot from Truck [this video] .
Cites user6972 · 2013-06 · Physics Stack Exchange · on “Will a ball thrown straight up in a train land in same spot (in real world)?”
I think this thread got spammed and floated to the top, but it reminded me of a similar demonstrations about frames of velocity. Watch this video where a ball is fired from a moving vehicle yet if conditions are just right it falls straight down. Ball drops straight down when fired from cannon [this video]
Cites Kyle Kanos · 2014-01 · Physics Stack Exchange · on “Can a bullet leave a gun and tumble to the ground?”
This has actually been tested and presented on television [this video] : the projectile will indeed fall straight to the ground to the stationary observer. However, you the shooter will view the projectile traveling with a speed of 40 m/s while the projectile sees you traveling with a speed of 40 m/s, thus the airspeed remains.
Cites WhatRoughBeast · 2015-12 · Physics Stack Exchange · on “Jumping from a moving train”
As is so often the case, Mythbusters has addressed the question. In this case [this video] they shot a soccer ball backwards off a moving pickup truck. They were going to have Tony Velachi tossed off by a treadmill, but the insurance folks nixed it.
Cites M. Enns · 2016-06 · Physics Stack Exchange · on “Speed and motion”
Yes indeed. I can't resist answering with This clip from Mythbusters [this video] which demonstrates exactly what you're asking about.
Cites DrTrunks Bell · 2019-02 · Physics Stack Exchange · on “I don't understand why escape velocity is necessary”
If you're in a car at highway speeds and jump out in any direction, are you still going at highway speeds? If you shoot a ball at 50mph with a cannon out of the back of a car that's driving 50mph it would stand still: [this video] So imagine Earth is the car where you're jumping out of, and the Earth is traveling around the Sun at about 30km per second. You'd still need to add 19km/s to the "escape velocity" in the opposite way before you come to a standstill and fall down towards the sun. 19km/s is a lot of fuel!