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Tricks67
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when we r considering a ball that is thrown at 45 angle, with the air drag present, why does it take longer to fall back after reaching its highest point?
Danger said:I think that the operative factor here is that upon descent the only forces acting upon the ball or bullet or whatever are gravity and air resistance. That same projectile typically undergoes several g's upon launch.
phinds said:So you reckon that if it was happening in a vacuum it would take longer to come down than to go up? And that it would git the Earth will less G force than that with which it was launched?
Danger said:'No' and 'yes', in that order. (I assume that the last sentence is supposed to have the words 'hit' and 'with' in it.)
As I pointed out, one of the factors is air resistance. The vacuum state would eliminate that. In normality, though, the object can be accelerated at any rate that doesn't achieve escape speed, but will always cease accelerating upon return when it hits terminal speed. Of course, the initial acceleration ends upon release from the launcher whereas gravity is constant, but the launcher power is ungoverned within engineering limits.
phinds said:I don't follow your logic
Danger said:Okay... I can see where there might be some misunderstanding due to my choice of words.
Try this:
If you fire a rifle straight up, the bullet leaves the muzzle at several thousand g's. When it reaches the apex of it's trajectory, it essentially stops and begins to fall (not exactly, of course, but close enough). On the way back down, it accelerates at 1 g. The terminal speed that it reaches will be nowhere near the muzzle velocity of the firearm.
Danger said:I very specifically pointed out that I am not referring to a vacuum. You, in fact, were the one who introduced that concept. I'm dealing with real-life situations, in which a vacuum plays no part. I have no idea of how you got so turned around on this.
Tricks67 said:why several 1000 g's in the beginning.....??
netgypsy said:Don't forget that air resistance varies with velocity so it is much greater when the object is traveling very fast so it will slow the object very quickly at the beginning.
Tricks67 said:when we r considering a ball that is thrown at 45 angle, with the air drag present, why does it take longer to fall back after reaching its highest point?
netgypsy said:This question had not yet been satisfactorily been discussed.
Consider two possible situations - one in which the launch velocity exceeds terminal velocity and one in which it does not.
Tricks67 said:an explanation stated that when its going up, the air resistance is in the same direction as the weight(mg) acting, and when its going down, the air resistance is in the opposite direction as that of the of the weight(mg)..thus in the second half of the motion (that is when its coming down) the speed is lesser..
what i don't get is that when its going up shouldn't the speed be lesser since the resistance and weight BOTH r acting to oppose the motion...?
The initial velocity of the ball can be calculated using the formula V = V0 cosθ, where V0 is the initial velocity and θ is the angle of the throw. In this case, V0 will be the magnitude of the velocity and will depend on the strength of the throw.
Air resistance, also known as drag force, acts in the opposite direction to the motion of the ball and can cause it to slow down and deviate from its intended path. The higher the air resistance, the more it will affect the trajectory of the ball.
No, air resistance cannot be neglected when calculating the trajectory of the ball as it can significantly alter the path and distance traveled by the ball. This is especially important for longer throws or throws with higher initial velocities.
The density of air can affect the motion of the ball by altering the amount of drag force acting on it. In denser air, there will be more air molecules for the ball to collide with, resulting in higher drag force and a shorter distance traveled.
Yes, the rotation of the Earth can have a small effect on the trajectory of the ball, known as the Coriolis effect. This is due to the rotation of the Earth causing objects to deviate from a straight path when moving over long distances.