Fast Driving

[Rharris9585]

If you are in a car travelling at 80 mph and you throw something into the air it and catch it again, why doesn't the object go hurtling through the front or rear windscreen if the car is travelling at such a speed?

[soonny]

Hahaha! Thats a good question. But ponder this, instead of imagining yourself throwing an object, try imagining yourself as that "object". You should be asking, "If I'm in a car travelling at 80 mph, why don't I go hurtling through the front or rear windscreen if the car is travelling at such a speed?".

 

Well the truth is, if you're in the car together with the object and the car is travelling at 80 mph, you and the object is travelling at the same speed at the same time as well. So if you throw an egg for example into the air, you are throwing it at 80 mph in the same direction as where the car is heading. Thats why it doesn't move forward or backward.  :)

[Rharris9585]

But surely when the egg is in mid-air and not touching anything it should hit the back window, as the car will have travelled forwards suffiiciently whilst the egg is up in the air?

An example to make my point is that if you were in a soft-top car or sitting on the back of a pickup truck and did the same experiment you'd have scrambled eggs all over the interior of your brand new soft-top sports car!?

[Mattk]

because everything in the vehicle is moving at 80 mph including the air but everything outside isnt

along the same lines,your argument says that if you jumped in the air whilst on a fast moving train youd hit the end of the carriage !!!!!!

[Nevin]

Also, consider a helium filled ballon, in your car travelling at 80 miles per hour. That could be up in the air indefinitely , and yet if you let go of it whilst travelling at 80 kpm it would still float in roughly the same spot (ie, up to the roof). Of course, if you had a soft top it would fly away.
Acceleration and deceleration are different though. You will notice that when your car speeds up and down, you do indeed move. This is one of the reasons it is extremely difficult to travel at the high speeds that can carry us across the universe. Its fine when the speed is constant, but if we tried to accelerate to light speed, our bodies would get squished in the back of the space ship!

[bernardo]

But surely when the egg is in mid-air and not touching anything it should hit the back window, as the car will have travelled forwards suffiiciently whilst the egg is up in the air?

 

No, because the egg is moving forwards at 80 mph in the first place.  In order to make it splat into the back window, you would have to cancel out the speed of the egg by throwing it backwards at 80mph, in order to cancel out the speed of the car (and its contents).

 

To put it another way, the Earth is zooming round the Sun at 19 miles per second.  But if we jump into the air, the Earth does not suddenly whizz off and leave us behind in space, because we are already going along at 19 miles per second as well.

[magicdice]

find a convenient marker point along a road. release the egg of yours out of your window at exactly this point, whilst travelling quickly. come back & you'll see that there's a smashed egg FORWARD of your marker, even though the egg appeared to rush backwards when you let go of it. see, it has to decelerate, because when you release it it's moving at 80mph or whatever your speed is

[robojoos]

inertia, duh!