Home
Creators
Search Recent Random
Posts
Search DMs Popular Hash Lookup Tags Random
Importer
Import FAQ
Register Favorites Keys Review DMs Logout
Community
Telegram ThePornDude
Home Creators Posts Import Register Favorites Logout

NEW VIDEO! 4 Rotation-related riddles (Patreon)

Published:
2017-04-12 15:45:29
Imported:
2026-06
Tags:

Content

This video includes a number of puzzles that have been proposed to me over the years including number 4 (Neil deGrasse Tyson) and number 3 (Simon Pampena). Check it out and let me know how many you get right!

Files

4 Revolutionary Riddles

Can you solve these four rotation-related riddles?

Comments

Jana Simmons

1. the cylinder contains something with an unequal mass distribution such that continuing to roll at one point would require raising that mass against gravity.

Jana Simmons

2. I believe that the bike will move forward for the length of the string pull till the pedal reaches a point 90 degrees from its starting point, at which time it will stop. 3. You need to travel 3 times your original speed to have the average be 2V1 4. This is a hard one... maybe the steam of a steam engine, but I'm not sure that counts as part of the train. To be fair, I'm a biochemist, not a physicist. I needed a tutor for physics!

Steve Ruis

#1 a water bottle #2 bike will move in the direction pulled #3 no can do, science boy (the second lap will have the same number of meters as the first but all of the time needed will have elapsed in the first lap) #4 the wheels, at least from 9 0'clock to 3 o'clock have to moving backward faster than train is moving forward, because pi.

viktor przebinda

#2: bike goes backwards. For the extreme case where the string is attached to the shaft of the pedal it'll clearly pull the bike backwards, perhaps there is a critical pedal length beyond which the string would push the bike forwards.

viktor przebinda

#4 left me thinking about wheels as well, but those move with zero velocity from 9 to 3 oclock. Unless you're measuring from train's frame of reference. I'm sure there are some gears that that move backwards faster but that doesn't seem to be what you're getting at.

Christian Baumgartner

#4 the flange of the train's wheel is below the running surface wheel-rail in the 6 o'clock position and moves backward from the contact point

Gregor Shapiro

I submit the following: #1: Container partially filled with liquid #2: The bike will move in the direction pulled #3: Cannot do it (or infinitely fast - but no one can run faster than the speed of light!) #4: The part of the train (excluding high speed motor or engine part which are unknown to us) moving backward are the points on the flange of the wheel below the rail (at the 6 o'clock position)

Rommel Nath

hi all what i think is- 1 ) you use a multiple section cylinder , it have hole in between section walls , you fill one of the section with a liquid or a sand . 2) bicycle Not move ,But if you apply greater force it will move backward with skating. Because you pull from back, paddle make wheel to move forward . 3)Velocity of your second round V2=V1(T1/T2)+2*V1. where T1/T2 is time ratio of time for first round to second round. V1 - first speed. 4) Train part which move back word is - Smoke , and also Air which you consider in control volume with respect to train. one more answer for it- A EXIT LIGHT Photons at the last of train

TPRJones

1. baffles dividing the interior into multiple chambers, and enough water draining between each to have the center of mass shifted back high enough to stop the roll while it drains. 2. the bike will move forward until the pedal is 90 degrees back, at which point further pulling will drag the bike backwards. 3. infinitely fast (Lap1:1x/1t=V, Lap2:ax/bt, Both:cx/dt=2V ... x is constant so a=1, c=2, d=1, and thus b=0) 4. the bit of flange below the rail

Iqra

1 Honey with some kind of light weight object in the honey 2. The bike will go towards you if standing in the back so backwards 3. Infinitely fast; if you have constant speed throughout 4. The part that sticks out the trains wheels that ride below the rails; flange