Motion Question...?

Question

Suppose a car is travelling at a constant speed in a straight line, with its windows open. Now someone fires a bullet from a gun (purely for science) perpendicular to the cars motion, such that the bullet goes through the open window of the car, through the car and out of the other open window on the other side. Assuming the bullet can travel fast enough does the bullet travel in a straight line (relative to an observer firing the gun) or does the bullet travel with the car as it goes through the car and then on its own as it leaves the car through the open window. Meaning does the bullet "enter" the frame of reference of the car for the brief time that it goes through it, and does it "return" to its own frame when leaving the moving car.

Well suppose a bee (replacing the bullet) flew through the open window, but as it entered the car it stopped dead in its tracks. Would the bee not then travel with the car, otherwise it would swiftly be plunged into the rear window. So what determines whether the objects would travel/not travel with the car?

Answer 1

Air resistance. The bullet travels through the car in a straight line, entering the car somewhat ahead of the point where it exits. It interaction with the air in the car is negligible. The insect, on the other hand, does interact, and will be rapidly accelerated to the car's speed. If the acceleration is done by the windshield, you will need to clean it at the next service station. Splat!

Answer 2

Let's ignore the effect of air drag and gravity. (I hope that's what you meant.)

Yes, the bullet will travel in a straight line as viewed by the shooter for the entire time. An observer in the car will see the bullet move in a straight line (for the entire time) too, but his observed line will be at a slightly different angle than the shooter's.

Both reference frames are usually considered to be infinite in size, covering all space. You can choose to use either frame at any time during the bullet's flight. The most convenient frame is chosen depending on what you wish to solve.

A key point for both Newtonian inertial reference frames and Einstein's special relativity's ref. frames, is that the physics must be the same in all frames. The mathematical coordinates will change, but the physics stays the same.

Answer 3

No the bullet would travel its own seperate path of trajectory independent of the car's path UNLESS the bullet comes into contact with anything solid in the car, however the air pressure created by the car's travel with open windows would affect the bullets path

Answer 4

The distortion of the bullet trajectory depends on the relation between the velocity of the car and that of the wind blowing out of the car. It could be easily calculated.
The bullet will not “return to its own frame when leaving the moving car”.

Answer 5

It will enter the frame of refrence of the car for a brief period of time but its really hard to predict or calculate the direction by which path of the bullet would deviate as there would be numerous forces acting on the bullet.

Answer 6

An object in motion will stay in motion unless another force acts upon it. The bullet would continue its same path unless some other force causes it to become displaced.

Answer 7

What is ironic about relative motioni is that we can only measure from one frame of reference at a time( that was Eisenberg Dilemma) and on the earth ,the earth is the frame of reference that we measure from. Why are teachers making something so simple on measurements to very complicated frames of references. which are really measuring points.

Answer 8

Im just guessing that it would maintain it own path straight through the car.

Answer 9

You do 1 thing, Ask some1 to fire into your car when u r driving and find out for yourself..