If you jump or throw things up in the air in a moving vehicle, why doesn't it move underneath the car?

Question

I know its in an enclosed space and all, but I still don't understand how if you jumped in a moving car you dont slam into the back windshield.

I've wondered this since forever

Answer 1

Ignoring the Latin and $15 words (I don't know who she is trying to impress), the answer is Relatively.  In this case, it is the relatively of the forward motion.  The forward motion of the car is at a certain speed and your speed is the same while in the car. Leaving your seat (jumping, bouncing, etc.) does not produce a zero speed relative to the car's speed.  If, for some reason, you were to have a zero speed relative to the car, you would smash (slam) into the rear window.

Answer 2

Which standard are u in boy?...learn this word by heart

I  N  E  R  T  I  A

Answer 3

Because the thing you throw up in the air is moving as fast as the car, before you threw it up in the air. As it flies up and down, and after it lands - it is still moving as fast as the car. We call this 'relative motion'.

The car's windshield shields whatever is inside the car from anything that could slow you down. Do this without a windshield and the thing you toss up will slow down. We call that 'drag'.

Answer 4

Why should you slam into the back? Think about it: the car is going 60 miles an hour; YOU are going 60 miles an hour. The fact of your jumping doesn't suddenly magically reduce your forward speed to zero. It has nothing to do with the fact that the space is enclosed; no force is forcing you backwards.

This is also the reason birds' nests aren't swept out from underneath them as the planet turns. This is an important concept in physics. Aristotle believed that there was an "absolute standard of rest," and that if you weren't being constantly forced, you WOULD come to rest with respect to the ground. But there is nothing magical about the ground that makes it more special than, say, the floor of your car. We now know that a body in motion remains in motion, UNLESS acted upon by an outside force.

Answer 5

Newton's First Law of motion can be simplified into the sentence "A body will stay at rest or continue at a constant velocity unless acted upon by an external unbalanced force."

In your moving vehicle, you are travelling at the same speed as the vehicle and when you jump, you continue moving forward at the same speed so, relative to the vehicle, you only appear to be moving vertically.  If they could see you separately from the vehicle (and in slow motion) an outside observer would see you moving in an arc - like the trajectory of a cannonball.

If you were able to sustain your jump for long enough i.e. hang in mid-air, friction with the air would eventually slow your body's forward motion relative to the vehicle and you would be hit by the rear window.

Answer 6

Go read Newton's first law.

Lex I: Corpus omne perseverare in statu suo quiescendi vel movendi uniformiter in directum, nisi quatenus a viribus impressis cogitur statum illum mutare

Oops, sorry: Every body perseveres in its state of being at rest or of moving uniformly straight forward, except insofar as it is compelled to change its state by force impressed.

So you jump up and then you just come down in the car.  You persevere in your uniform forward motion, since nothing is compelling you or impressing any forces on you to change that motion.