how do aerodynamics affect falling objects?
412208
it can either increase the speed of the fall by reducing the air resistance or decrease it by creating more air resistance. think parachute and missle.
868820
the answer above is wrong to a degree - in your example i would have to imagine falling through a vacuum therefore if he didn't touch the sides his momentum would carry him to the other side and then back again over and over\n\nthe answer above ( 1st ) assumes air resistance would slow him down but he would go back and forth for a long time before stopping\n\nthe gravity would decrease on the way down and increase on the way up but not in the way you think what would happen is that the gravity would be pulling from the side more and more the deeper you got ( so the effect is only virtual) you would always be in a 1g field it is just the direction(s) of the pull that would change\nthe direction of the most mass at any one time would appear to be down and at the center all pulls ( 360 degrees ) would seem to cancel one another ( but they would still be there )
616393
Any thing moving through the atmosphere experiences the force of gravity and a drag force due to the friction of the air as it moves through it. When the object is falling, the force of gravity is directed towards the ground and the drag force directed upwards. As the body moves faster, the drag force becomes larger and larger until it equals the force of gravity and the object then falls at a constant velocity. This velocity is called the terminal velocity. For a person jumping out of an airplane, in skydiving, it is roughly 120-150 miles per hour. The terminal velocity of a water drop is much smaller. A large raindrop (5 mm in diameter) will fall at a velocity of around 20 mph. If you get hit by a large raindrop you will definitely feel it. However its still not large enough to cause much pain. The smaller the raindrop the slower it falls and hence the less energy it has when it hits you. If you dropped a grain of sand the same size as a raindrop it wouldn't hurt either. Pebbles are much heavier than raindrops and hit your head with a lot more force. Force is directly proportional to the mass and velocity of an object.\n\nOf course hail, which is really just a bunch of frozen raindrops which have joined together, is actually less dense than water but will certainly hurt due to its large mass.
1183225
The instant an object is released as it is thrown upwards, it begins to accelerate downward.  This downward acceleration is caused by gravity (the force of weight, m*g, acting downward on the object).  Although the object may continue to travel upwards for a brief time, it is continually slowing in the upward direction as it accelerates towards the ground.\n\nObjects "fall" towards the ground (in the direction of the center of the Earth's mass) since that is the direction of the force of gravity is exerted on them.  An object cannot "fall" up since there is no net force acting in that direction.
892916
I think the key here is that the objects will be rolling down the plane; thus the gravitational potential energy they have is not only converted into translational kinetic energy, but also into rotational kinetic energy.\n\nAnyway, I would approach this from energy considerations.  Start by calculating the amount of potential energy the objects will lose by falling a distance of 3 m.  (For both, this will simply be PE = m g h).  Equate this to the total amount of kinetic energy the objects have at the bottom of the ramp (translational plus rotational, or 0.5 m v^2 + 0.5 I w^2 where I is the moment of inertia, and w is the angular velocity.)\n\nSo, you need to know the moment of inertia for a disk and a hoop.  The hoop I know off the top of my head, I(hoop) = m R^2.  The disk, I looked up to find I(disk)=0.25 m R^2.\n\nFinally, recognize that as they do not slip, you can relate the angular velocity w, to the translational velocity v:  v=2 Pi R w.\nOnce you do this, you find that the kinetic energy depends only on the velocity v, so we have one equation with one unknown.  Just solve for v with the two different values of I, and I think you ought to find that the disk will be moving faster than the hoop.\n\nSorry for being long winded.... but I hope it helps.
882493
Air drag would not be negligible. However if it was, It wouldn't necessarily take 7 seconds to fall. This would only be the case if the firework accelerated up constantly at 9.81m/s2. It could be more or less than this.\nThe acceleration vertically (downwards) would be 9.81m/s2 like everything else that falls\nthe path would be a parabola effectively it is a y=x^2 as the horizontal velocity is linear (proportional to t) and the vertical velocity is a function of t^2\n\nAgain air drag has a huge effect. Acceleration down would stop in about 0.5 second.
944784
I think stunt bags are almost atmospheric pressure. The safety is produced by having small air vents that allow the air inside to escape - just like a pile of cardboard boxes, the inside is basically atmospheric. The 'pillow' effect starts when the falling body first hits the bag. But from then on, the air is forced out of the air bag to absorb the weight of the falling body. If it were a sealed bag, the falling body would bounce right off of the bag.
845422
This is related to Newton's law: An object in motion or at rest will stay in motion or at rest unless acted upon by an external force.\n\nTo elaborate, an object travelling in a straight line will keep on travelling in that straight line at a constant speed unless something acts on it.\n\nWhen you are in the car with your ball, everything in the car is travelling at the same speed, so you through the ball up and it comes straight back down. But if you throw the ball up and then jam on the cars brakes, the ball will keep moving at its original speed but the car is slowing down, so the ball would fly forward into the front windshield.\n\nLast point, if you throw the ball out the window, it will appear to fly backwards - It is just slowing down compared to the car because unlike the air inside the car, the air outside is at rest, so the ball will be flying through the air at a high speed and the wind drag will slow it quite rapidly.
1075806
I assume that you mean that the object is perpendicular to the velocity of the wind.\n\nConsider a flat plate, area A, against which a wind of speed v is blowing.  The air has a density of p.  All measurements are made in a consistent unit system of course.\n\nIn one second a mass of air will be brought to rest, this mass is given by A x p x v\n\nThe momentum change of this air is therefore A x p x v²\n\nwhich gives the force on the flat plate.  Your object will also have a drag coefficient (Cd) the more streamlined the object is the lower it's drag.  So the total force becomes:\n\nA x Cd x p x v²\n\nYou will have to look up the drag coefficient for your object in a text.
846849
1) Yes if you neglect the effect of wind resistance\n2) Yup, because some of its momentum is transferred to the ball (Total remains constant)\n3) Yup, since it was in zero momentum before it was hit and now it has a speed\n4) Ya, all happens
1039676
Newtons second law - blance of momentum.\n\nWhen the force acting on the mass to accelerate it is the maximum that the engine, atmosphere, and gravitational attraction to the earth can produce, and those forces are balanced by the the forces acting on the mass to slow it down, then the mass is at its "max speed".\n\nDensity of the air is affected by altitude, temperature, humidity, and weather.  For horizontal, noncompressible flight, that density is a major component of the "dynamic pressure" and therefore the drag.\n\nA very simple model of drag is D=0.5*rho*U^2 *Cd*A where rho is the density of the working fluid (atmosphere), U is the freestream speed of the air, Cd is the coefficient of drag of the airplane, and A is the frontal cross-sectional Area.\n\nIf you set max thrust equals this drag, then you can math out what U is, and call it the max speed of the plane.  If the plane has a headwind or tailwind then its absolute speed will vary.\n\nIf the plane approaches mach then stranger and more energy-demanding phenomena kick in.  If the plan is going beyond the speed of sound there is a third, also complex description for the drag.\n\nIf you are using a prop driven plane then you cant just assume that the thrust equals the planes horsepower, you have to consider the efficiency of the prop and there are equations for that.\n\nDetermining the Cd for a plane is complex because the wing, body, and tail all interact to change the overall Cd.
148681
Only objects of the same mass (Weight) fall at the same speed. Objects of different size (Shape) can fall at different speeds.
897109
atmospheric pressure decreases as altitude increases.\n(think about gravity)\n\nan object that floats is less dense than the fluid it floats in.\n"A piece of the object weighs less than a piece of the fluid the same size."
106773
depends on the acceleration of the airplane or object. this found by vector addition. example: if an airplane or a rocket is falling freely (god forbid) all the objects inside will have 0 weight.
478612
It depends on the object.  Tests with coins have measured velocities too low to cause signifcant damage to the average human head.\n\nTerminal velocity, in this case the maximum speed a falling object will reach, depends on the shape of the object, the accelleration, and the qualities of the atmosphere.\n\nWhen an object is dropped near earth, it accellerates towards the earth at about 32 ft/sec/sec.  It goes faster and faster until the frictional drag from the air, has a slowing effect equal to the speeding effect from gravity.  From that point on it will stay approximately the same speed.  A feather has a very low terminal velocity.  A crowbar has a much higher one.  Its all about friction in air.\n\nA penny dropped near a planet without an atmosphere would accellerate toward the planet, getting faster and faster until it hit.  This scenario could be deadly for the space-suited person in the way.\n\nWater falling has an additional complication in that the air drag changes the shape of the water droplet and that in turn affect the drag.  A water droplet's changing shape on impact also affects the damage it might do a person.
287006
Terminal Velocity.  It depends on the weight of the object because it is based on gravity.  If there is force applied to the object then it could travel faster for moments then gravity would slow it down.
1036772
depends on your definition of flying, which is commonly known as moving through the air using wings or an engine, but good question though. but IMO flying is controlled falling :), since if you look at the physics of it, you are constantly trying to counter gravity which is towards the center of the earth.