Has any of you physics people ever thought of this??? This seems like common sense.....?

Question

This is just me being curious...

If you were in your car going 70 MPH with the windows up, no air resistance and there was a lady bug sitting inside of your car in the back seat. In order for it to fly from the back seat of your car to the front seat would it have to fly faster then 70 MPH???

Now, I know that if it was something such as a grasshopper, and it was in the moving car and wanted to hop up front it would already be moving at the same speed as the car and would have the same initial velocity as the car, plus the additional velocity provided by its legs, and would make it to the front seat.

If the same is true for the lady bug then what is the difference between, the car scenario, and a lady bug flying down the high way at 70 MPH with a bubble around it??

At what point in flight would the lady bug loose the initial velocity gained by the movement of the car and get sucked to the back seat????
Can bugs fly 70 MPH? I don't know the answer, but we've all seen it happen.

try not to get to crazy with its speed with reference to this.....all I really wanna know is if the bug is using the same amount of energy to move from the back seat to the front, as it would if it were attempting/flying +70 MPH.......


Am I weird for even wondering this???? lol

Answer 1

The speed of the lady bug in your question is always relative to the observer.
In your question, there are two obvious choices of the reference frame the observer sits in….either on the ground outside the or in the car.

To the observer outside the car on the ground, they see the car (and everything inside of it, including the lady big) traveling at X mph.
To the observer inside the car, they see the car (and everything inside of it) stationary and they see the ground outside the car moving by them in the opposite direction at X mph.
Here I use the speed X mph to generalize the situation more than specifying a specific speed, like 70 mph.

You asked if the lady bug would need to fly faster than “70 mph” in order to travel from the back seat to the front seat of the car. But in what reference frame? Obviously you were referring to a speed measurement made by an observer on the ground and not inside the car.
To someone outside the car on the ground, they would measure the speed of the car to be X mph. In order for the lady bug to move forward inside the car, the lady bug would need to move faster than the car. The observer on the ground would measure the speed of the lady bug [relative to the ground] as some faster speed, Z mph, where Z > X.
To someone inside the car, however, they do not see the lady bug moving at Z mph….they would measure it as being much slower. They [the observer(s) inside the car] would measure the speed of the lady bug [relative to the car] as Y mph.

Why the different speeds you ask? It is because of the different in the frames of reference

To the observer on the ground, they see the lady bug’s speed as Z mph. But really, Z mph is the sum of the speed of the car (X mph) and the relative speed of the lady bug inside the car (Y mph). Z = X + Y.
Bug someone inside the car does not “see” the speed of the car in their measurements since the car is not moving in their reference frame (the ground is moving past them, not the over way around), so they just see the relative speed of the lady bug to the car.

So if the car was traveling at 70 mph and the lady bug flew from the back seat to the front seat of the car, then yes, to someone watching from outside the car on the ground, it would look like the lady bug was flying faster than 70 mph.
But to someone watching inside the car it would look normal, they would see the lady bug flying at whatever speeds lady bugs fly at.

But now you might ask,
“But what happens after the lady bug takes off from the back seat and is suspended in the air inside the car?”
Well I am glad you asked.
Newton’s first law of motion tells us about a property of matter called inertia (an object in motion will stay in motion unless acted upon by a force / an object at rest will stay at rest unless acted upon by a force).
To the observer on the ground who sees the car flying past at 70 mph, the already see the car/passengers/lady bug traveling at 70 mph. The lady bug is already moving as fast as the car and inertia tells us that it is going to keep moving at this speed unless some force acts on it.
What the lady bug jumps into the air, it has a speed of zero mph relative to the car, and this will not change speed just by jumping up into the air. As the lady bug flies forward, it exerts a force which pushes it forward and changes it speed (increases) and causes it to move forward and allows it to move to the front of the car.

Answer 2

Yes, you are weird.... you might be a fledgling science nerd.... but the world needs lots more science nerds. Kudos for wondering about the relative velocity of a ladybug.

If the bug is in the car with you, its already doing 70 mph to an observer outside the car. Inside the car it appears to be at rest (until it flies to the front seat). You (in the car) see it move at about 3 mph but to the (stationary) observer outside the car the bug appears to go 73 mph, but its not really flying that fast, get it?

Answer 3

The air around the ladybug is traveling at 70 MPH so the same rules apply to her as to her grasshopper friend. If she was in a bubble outside the car, the bubble would have to be moving that speed for her to keep up. She won't get sucked to the backseat unless you open a window.

Answer 4

The air in the car is also travelling at 70mph down the road. Flying things have an airspeed - their speed is measured relative to the air. The ladybug experiences nothing unusual when it flies from the back to the front seat. In fact, if you have leather seats, it might think it is flying from one cow to another. Ladybugs aren't that bright.

Compare - the rotation of the earth means that the ground is travelling at over 1000mph. Birds can't fly at 1000mph can they? No - the air is moving at the same speed as the earth, and so birds fly around in the 'moving' air as though it was standing still. For all intents and purposes, it is - it's an inertial reference frame.

Answer 5

If the lady bug's normal flying speed outside on a windless day is 10mph.
In your enclosed car, it would also fly at 10mph with no difficulty but that is only in relation to the speed of the car.
It would be travelling at 80mph relative to outside.