When a closed Van takes a left turn, and has a helium baloon in it, which side the baloon will move and why?
140469
The helium balloon will continue to travel forward until it collides with the right side of the van that is now moving towards the balloon.  Once the side of the van and the balloon meet, the balloon will travel to the left.\n\nFrom the perspective of someone in the van, the balloon will APPEAR to move to the right.
690572
against the direction of travel.
971245
to the left hand side
10432
The balloon is filled with hot air by the burner.  The hot air inside the balloon rises because it is lighter than cold (or cooler air).  assuming you mean't a hot air balloon.\n\nNobody is sure about helium ballons because we always suck the helium out so we can talk weird.
757156
How about someone is run over by a car.  The owner of the car says they left it in neutral on a level parking lot, and must have forgot to set the parking brake -- the car started rolling forward before they could jump back in and stop it, and the car ran the victim over.\n\nThis can be disproven because Newton's first law (the "Law of Inertia") states that an object at rest will stay at rest until acted on by an outside force.  Since no outside force was present (the parking lot was level so no gravitational force acts to accellerate the car horizontally) and the car itself was turned off, it cannot possibly have "just started to roll by itself" -- the car owner intentionally ran the victim over.\n\nWhy would he do that?  Well I guess that will be the fun and imaginitive part of the assignment!
887467
Im a little rusty on the thermodynamics, but lets see if this helps.\nV/T (initial)=V/T (final) since no gas is lost or added  Raising the temperature on a container that is free to expand does not change the pressure, so you can find the change in volume with temperature.  Since V=A*h, you can find h.\n\nNow, the problem is that the vessel is not entirely free to expand, and acts on a spring, with force equal to F=k*h.  This force is related to the pressure created by the expanding vessel as simply F/A.\n\nAll values are given, so I think you are set.
733139
It follows Newton's law that for every action there is an equal and opposite reaction.  It's usually a wheeled vehicle that flings something backward in order to move forward.  The simplest type uses the jet of air escaping from an inflated balloon.
622535
It should explain the loading phase on the side of the container
628477
it is called a gyro, it goes right under the neck if the handlebars. it is really a sealed bearing that turns when pulled. think of a baring with posts on the out side and the inside if u grab all of the posts then u can spin the baring all the way around will just put break cables on the post and their u go. a Gyro.
891931
initially only 10-29% of air is filled because the air inside is heated it naturally expands and occupies the rest of the volume when it expands the density of helium decreases and hence the baloons goes up because the density of air inside is leser then the air outside
1068628
If its on an axis it turns, if its not it it rolls
135305
YES!  It's perfectly possible to _build_ such a car.  If the magnet is just attracting the car, it would pull forward on the car, and the car would pull back on the magnet.  Nothing moves.  If the magnet is attracted to an object ahead, the rig would move forward but would stop when the magnet got there.
414472
HAHAHAHA You all forgot about our little friend called drag! Inside or out the ball has a drag force acting on it by the surrounding air. Like stated before the air in the car is moving with you, and the car, and the ball all the same and the drag force on the ball at this point is negligible. This is not the effect of a vacume, a vacume is the absence of air. is it possible for there to be no air in the car? NO, Sooo.. outside on a bike or where ever, you are traveling at a speed where the balls light weight will be significantly affected by this drag force and it will cause it to slow down as you throw it up and while you keep riding on un affected by the static(motionless) air, your ball only has one force acting on it, air drag causing it to slow behind you.   test this by throwing a variety of same shaped objects while riding and you will see that the one with the most density will keep up the best. try a marble V.S. a ping pong ball.  then do it in the car
103089
Tell it to go in the other direction
114124
Probably the simpliest way I can think of is just to strap the balloon to a set of wheels and position it so that the opening is point in the opposite direction you want the car to move.  When the balloon is released, the air can escape out the hole and propell the car forward.
1130182
Um... I think maybe pull... if something is rotating/turning it is creating it's own little gravity field (I think!) therefore making it easier to pull.  I'm no scientist but this is an educated guess.
605104
You misunderstand the process going on.  The car isn't absorbing convective heat from the surrounding air.  It's absorbing radiant heat from the sun.  It gets so hot because the closed car acts as a greenhouse containing the heat.  Also, a close car is pretty well insulated so it can't lose the heat very well through convection.