Ok, ive been arguing for a while about this, its probably easy for you to answer, but I need to know which is true and which is not. Here is the scenario:

Lets say your driving a car at a moderate speed, 40 mph, and you stick your hand out the window, and you're holding a tennis ball, and you drop it. For what reason does it "fly" back?

Ok, now the same scenario, but there is no air resistence, what happens when you drop the ball?

Thanks for the help.

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Doc Al
Mentor
Dio. said:
Lets say your driving a car at a moderate speed, 40 mph, and you stick your hand out the window, and you're holding a tennis ball, and you drop it. For what reason does it "fly" back?
The ball appears to "fly back" with respect to you in the car due to the air exerting a force that opposes its motion, thus slowing it. (Viewed from the road instead of the car, the ball would go forward with an initial speed equal to that of the car, but be quickly slowed by the air.)

Ok, now the same scenario, but there is no air resistence, what happens when you drop the ball?
It maintains its horizontal speed alongside the car. (It drops to the ground, of course.)

yeah

The reason it so called flys back is that you in your car are moving at 40 mph. Now the ball while in your hand is moving 40 mph. When you let it go the ball then quickly decelerates due to friction and air resistance. so the ball slows down and you keep going your 40 mph. Now with no air resistance i think that means there are no frictional forces acting on the ball. This means that the ball will then travel with you until it hits the ground and then it will fly back due to it just hit the ground and lowerd its speed. In the end it is actually kinda you flying forward than it flying back.

You can experience it if you loosely hold your hands out of your car. Your hands will fly back due to air resistance. But - BE CAREFUL

Resnick Halliday is the book which as far as I have read the one which gives a good explanation about air resistance.