how come a fly inside a running vehicle doesnt hit the rear end of the vehicle..?
112520
He is the designated driver
816243
When an object (like the truck) hits a solid wall then the wall forces it to stop suddenly. \n  The wall and the truck have a certain elasticity, though small. When the truck touches the wall it starts pressing on it and the wall bends very little. It bend in a very short time too. During this small period of time the object's momentum changes from "mv" to "0". The force is the ratio F= (m*v) / t. Because t is very small the force exerted is very big and it crushes the truck's front end.
390002
I assume you mean a fly that is flying inside a moving train?\n\nUm...the air must move with the train, I guess.  Um...you've just blown my mind.  I have no idea.
542150
Because the air and all objects inside of the car are going the same speed as the car, try driving around a corner with a helium ballon. If you take a right corner the ballon will go to the right side of the car while you go to the left side.
185627
Duh...it's A*S! And you told it wrong...\n\n"What's the last thing to go through a bugs mind when it hits the windshield?"
541091
Inertia means two things:\n\nAn object at rest will stay at rest, unless another force acts on it.\n\nAn object in motion will continue in motion, unless another force acts on it.\n\nAny force which changes the motion of an object -- the speed and/or direction -- is called acceleration.\n\n...You're riding along in your car.  Both you and the car have inertia; that is, you're both in motion, and will continue to move until something changes that.\n\nThe car runs into a wall, which certainly makes a big change in the car's motion.  You, on the other hand, and anything else inside the car that wasn't strapped down, will continue to move forward because of your own inertia.  Without a seat belt or air bag, your body will continue to move forward through the windshield, which is undignified, extremely painful, usually fatal, and a big drag to clean up.\n\nSo:\n\nA)  Seatbelts put you more "in contact" with the car; which is to say, any force which affects the inertia of the car will be more efficiently transferred to your body -- though not *so* efficiently that you go "splat" like the rest of the car; they just restrain you from continuing forward into the windshield.\n\nB)  A head rest acts as an accelerator for your head.  If the car accelerates suddenly (such as when somebody runs into the back of your car), the car's seat transfers that acceleration to your body.  The head rest acts as an extension of the seat, so that your head is also accelerated and doesn't get "left behind" because of its own inertia.\n\nC)  In practical terms, a force which is applied directly opposite to an object's direction of movement is called "deceleration."  It's still the same thing as acceleration, but we treat it as if the speed an object is going in a particular direction is being decreased in the same direction.  When the car hits the wall, as your body's inertia propels you forward, the air bag acts as resistance to that forward movement, decelerating the forward motion of your body.\n\nThe point to all three of these is to gently transfer acceleration to your body.  A car is much more rigid than your body (for instance, if you were to accelerate really hard, the rear bumper isn't going to get left behind), and is able to take much more drastic changes in its speed and direction.  Your body is much more fragile (and much more valuable) than a car, so seat belts, head rests and air bags are used to ease the changes in acceleration.\n\nAs you know, falling off a tall building isn't what kills you, it's the big fat splat at the bottom.  When you fall, your body accelerates down with a force of one G (which stands for earth's gravity), which your body can handle quite well.  But when you hit the ground, the ground acts to accelerate you in the opposite direction (up) *very* quickly, with much more acceleration than your body can stand.  If there's a big enough air bag to land on, it will slow down the up-acceleration (or down-deceleration, whichever way you look at it) to something that your body can handle.  Now, turn the whole setup sideways, and that's the reason for seatbelts, air bags and head rests.
104208
I'm pretty sure on a web only some of the web is sticky. The spider just knows where to put its feet. I think... Or maybe its just the opposite of how a fly lands unside down on the ceiling.
44366
einstein's theory of relativity.  in the frame of reference of the car, you are stationary, the fly is stationary, and everything else in the car or moving with the car is stationary. this is why if you are in a car and drop a book onto the seat, it goes straight down, not toward the back. it is going at the same speed as the car and therefore is still relative to the car. there is no force acting on it to make it behave otherwise.  that's why you don't feel anything in a car unless you're accelerating or decelerating. so you feel like you're pushed forward when the car is coming to a sudden stop. because then there's a force stopping the car, and therefore you, so you feel it. in this case, the fly would also go flying(no pun intended) to the front of the car.\n\nif this is still unclear, think of the earth. the earth is rotating with a speed of over 1000 m/s, but you don't feel it. that's because you're moving at that same speed, you're stationary relative to the earth so you feel stationary because your frame of reference is the earth.
378959
It could actually help another vechicle, I don't know about a large truck(semi?) but here read this\n\nThis slipstream effect works in the following way. As a single car races around a track, it creates a "bubble" of high-density air in front of it and a bubble of low-density air behind. The difference in the pressure between these two air pockets creates drag, the force that impedes motion. This drag force limits the top speed the car can attain. But if a second car pulls up behind the first, the slipstreams created by the two merge so that the first car losses its aft bubble and the second car loses its front bubble. This effect reduces the drag force each car experiences and both are able to travel slightly faster. \n\nhttp://www.aerospaceweb.org/question/aerodynamics/q0092.shtml
1176333
The fly floats in the air. The air in a moving car more are less travel with the same speed. The fly floating in air inside car does not hit on the sides of the car. While travelling in open lorry, if you throw a ball vertically in the air, the ball reaches your hand again, even the lorry moves. This is because, the ball also got the momentum to travel along the lorry while it is in the air. The will work out for certain heights only.
1041922
Flies land on the ceiling by flying close to it, sticking their front pair of legs above and in front of their heads (a la Superman), and grabbing onto the ceiling as they fly under it. Their inertia causes them to do a half-backflip, pivoting around their front legs. They then grab hold with their middle and back legs.
664508
because of inertia it will be traveling at 60mph as it leaves the car\nbecause of the fly's body shape theoreticaly it would give it lift assuming that the fly was facing foward\n\nrealisticly it was facing sideways, so the air would be traveling over its body sideways it would have been plummeted into the ground and its wings would have been ripped off
558814
that's called relative velocity.....for the bee the car was still.....
1105380
some do..some don't. it depends on the kind of racing.. kind of be stupid to put them on something that it's just going to get knocked off of.
968105
because it would CHANNEL that air flow DIRECTLY onto the vehicle behind the truck and thats not safe.
47938
The first answer is correct. I think for the second answer, the questioner would probably be wondering...well, if the helicopter takes off with the same velocity as the earth, since the heli is now hovering and the earth keeps on turning, why doesn't the earth spin past the helicopter...\n\nAnd that is simply because the atmosphere is turning around with the heli, like the first answer stated.\n\nJust wanted to elaborate with another example. A fly takes off from the dashboard of a speeding car with its windows closed. Does the fly stay in air or, since the fly is now seperated from the car, does the car rush forward, making it seem like the fly is hurtled to the back of the car?\n\nEven in this case, the air inside the car is being brought along with the car at the same speed. Therefore, the speed of the fly relative to the car will always be 0.
376537
Ask the fly :)\n\nI suppose it would depend on the fly. Maybe a very young fly would be slow, and turn over early so as not to hit its head on the roof. A teen fly would speed up there, and flip round at the last moment. A middle-age fly would calmy, and smoothly swoop over and turn to land. An old fly wouldn't be able to dodge the swatter.