The force of air resistance acts oppose the motion of an object moving through the air. A ball is thrown upward and eventually returns to the ground.(a)As the ball moved upward, is the net force that acts on the ball greater than, less than, or equal to its weight? why?(b)repeat part (a) for the downward motion of the ball
2006-11-02 16:53:27 · 6 answers · asked by FIGUREsk8er4life 1 in Science & Mathematics ➔ Physics
force of air is less than it's weight therefore it rises and it drops.
a=b
2006-11-02 17:01:40 · answer #1 · answered by lnfrared Loaf 6 · 0⤊ 0⤋
a) The net force can either be greater than, less than, or equal to the weight of the ball. It is a net force, so it can be of any magnitude greater than 0. It is the force that the ball was thrown upward which has to be greater than the sum of the weight of the ball and the force of air resistance. Otherwise the ball will not go upward. We can try this by lifting a heavy rock. If our force is not big enough we might not even be able to move the rock. But a muscle man could maybe do better. He could throw the rock upward at a force maybe twice the weight of the rock, such that the net force could be equal to the weight of the rock, if we neglect air resistance. But as we said the net force could be any magnitude greater than 0.
b)The net force will be less than its weight. The downward force acting on a falling body like the ball is opposed only by air resistance, such that the net force becomes less than its weight. If air resistance is ignored, the net force will just be equal to its weight.
2006-11-03 01:27:18 · answer #2 · answered by tul b 3 · 0⤊ 0⤋
You cannot say that the net force is greater than, less than or equal to the ball's weight. It also depends upon the environment conditions. Suppose u try to throw a ball down towards a large fan which is currently switched off. In this case obviously the balls weight is greater than the air resistance.
But if u switch the fan on at full speed and then throw the ball, at one moment the ball will move toward the fan because of the initial force given to it but at the other moment the air resistance dominates the balls weight and throws it in other direction. This concept can also be applied when throwing the ball upward.
So, in general we cant say that the ball's weight dominates the air resistance, it depends upon the environment in which we are doing experiment.
2006-11-03 06:48:27 · answer #3 · answered by Napster 2 · 0⤊ 0⤋
Both up and down has only two existent forces: gravity and air resistance; where gravity always points downwards and is F=mg (the weight).
When it goes up, (a) air resistance act DOWNWARDS while gravitation (weight) acts DOWNWARDS, therefore the two downward forces add up to be GREATER than the weight.
When it goes down, (b) air resistance acts UPWARDS while gravitation (weight) acts DOWNWARDS, therefore the sum of the two forces would make a SMALLER net force than weight.
Hope I helped :)
2006-11-03 02:34:27 · answer #4 · answered by insert_username 2 · 0⤊ 0⤋
The only forces present in this problem are air resistance and weight. Weight pulls down and is always constant. Air resistance pushes the ball in the direction opposite to its velocity. When the ball goes up, weight pulls down and air resistance pushes down.
Air resistance + Weight > Weight.
When the ball is falling, weight pushes down, but air resistance pushes up.
Weight - Air resistance < Weight.
2006-11-03 01:21:15 · answer #5 · answered by Biznachos 4 · 0⤊ 0⤋
upward
F=-mg
downward
F=mg
2006-11-03 01:18:51 · answer #6 · answered by Anonymous · 0⤊ 0⤋