The discussion centers on the principle that horizontal speed does not influence the time it takes for an object to fall vertically. Participants assert that the only forces affecting vertical fall time are vertical forces, regardless of horizontal velocity. They emphasize the distinction between idealized scenarios and real-world situations, where factors like aerodynamics and initial conditions can complicate outcomes. The conversation highlights the importance of understanding physics concepts, such as Newton's laws of motion, to grasp these principles accurately.
PREREQUISITESStudents of physics, educators teaching motion concepts, and anyone interested in understanding the dynamics of falling objects and projectile motion.
user079622 said:
Why my intuition fail, why I am wrong?
Without put problem on paper, you will say that time duration is equal?PeroK said:The universe doesn't care about human intuition.
Yes, I can say it is true from my experience with shooting and ballistics. When we calculate the drop of a bullet fired horizontally, we take the horizontal flight time from the gun to the target, and use that time to tell us the vertical drop.*user079622 said:Without put problem on paper, you will say that time duration is equal?
Yes. Unless the speed is sufficient for the curvature of the Earth to become relevant.user079622 said:Without put problem on paper, you will say that time duration is equal?
Because your intuition is trained on real world situations (where many factors are at play), not idealized scenarios (which are meant to demonstrate one aspect in isolation, and are supposed to be easy to solve).user079622 said:Why my intuition fail, why I am wrong?
Watch this video of a classic demonstration. Is what you see consistent with your intuition?user079622 said:Why my intuition fail, why I am wrong?
This is the reason that the underlying laws of nature went undiscovered for so long. Newton saw what no one else had previously seen: that hidden beneath the variety and complexity of motion lay four laws - the three laws of motion and the law of gravitation.A.T. said:Because your intuition is trained on real world situations (where many factors are at play), not idealized scenarios (which are meant to demonstrate one aspect in isolation, and are supposed to be easy to solve).
For a frisbee, the horizontal velocity obviously matters for the time it stays airborne, because of its aerodynamics, which is often neglected in idealized problems.
Yes, I know if I jump in train, I will land at same place if train travel at constant speed.kuruman said:Watch this video of a classic demonstration. Is what you see consistent with your intuition?
Do you think his discover of calculus is even bigger then laws of motion?PeroK said:This is the reason that the underlying laws of nature went undiscovered for so long. Newton saw what no one else had previously seen: that hidden beneath the variety and complexity of motion lay four laws - the three laws of motion and the law of gravitation.
What if the train is not moving at constant speed, but it accelerating? Watch this especially the last part when the acceleration is provided by tilting the track away from horizontal. The result will be the same whether the cart is released from rest down the incline or given a push up the incline.user079622 said:Yes, I know if I jump in train, I will land at same place if train travel at constant speed.
Ball is fired at angle in last part. Oblique shotkuruman said:What if the train is not moving at constant speed, but it accelerating? Watch this especially the last part when the acceleration is provided by tilting the track away from horizontal. The result will be the same whether the cart is released from rest down the incline or given a push up the incline.
An angle with respect to what? "Oblique shot" does not explain much.user079622 said:Ball is fired at angle in last part. Oblique shot
Respect to horizontalkuruman said:An angle with respect to what? "Oblique shot" does not explain much.
If ball is fired vertically, it will fall behind truck.kuruman said:An angle with respect to what? "Oblique shot" does not explain much.
Vertically according to whom?user079622 said:If ball is fired vertically, it will fall behind truck.
The only forces affecting the time an object takes to fall vertically are vertical forces.user079622 said:He didnt plug horizontal speed in any equation, which implies it is irrelevant for this problem.
Vertically respect to ground, parallel with gravity direction.jbriggs444 said:Vertically according to whom?
If vertical with respect to the rest frame of the ground then yes, the truck will move away forward before the ball falls.
If vertical with respect to the truck then, to a first approximation, it will fall back into the truck. To a better approximation, Coriolis will do its thing.
No without help of textbook.kuruman said:Assume that the cart is moving down the incline with speed ##u## when the ball is fired with speed ##v## in a direction perpendicular to the incline. The angle of the incline is ##\theta##. Can you show with equations, not intuition, that the ball will fall back into the cart regardless of the values of ##u##, ##v## and ##\theta##? Ignore the Coriolis effect mentioned in the previous post.
OK, this is not a class exam. Consult with your textbook and once you get your solution post it here. There are more than one ways to get the answer.user079622 said:No without help of textbook.
It's not about what 'vertical' means. It's about which reference frame measures the velocity to be vertical. Gravity has the same direction in all frames, but velocity vectors are frame dependent.user079622 said:Vertically respect to ground, parallel with gravity direction.
user079622 said:
He didnt plug horizontal speed in any equation, which implies it is irrelevant for this problem.
My intuition say that if I throw a bullet from 1.5m height, with horizontal speed of 10m/s it will take less time to hit the ground, than if I shot this bullet from gun at 1000km/h in horizontal direction.
Why my intuition fail, why I am wrong?