Calculating Average Force Due to Air Resistance in Projectile Motion

AI Thread Summary
To calculate the average force due to air resistance on a projectile with a mass of 0.750 kg and an initial velocity of 18.0 m/s that reaches a maximum height of 11.8 m, one must consider the energy lost to air resistance. The initial kinetic energy can be determined using the mass and initial velocity, while the final potential energy is derived from the maximum height. The difference between these energy values represents the work done by air resistance. If air resistance were absent, the projectile would reach a higher altitude, which can also be calculated. Understanding these energy transformations is crucial for determining the average force due to air resistance.
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A projectile has a mass of .750kg and is shot straight up with an initial velocity of 18.0m/s. If the projectile rises to a max height of 11.8m, determine the magnitude of the average force due to air resistance. Can anyone help me with this?
 
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The energy lost due to air resistance equals the work done by the air.
 
I don't understand?
 
Suppose there is no air resistance. Can you calculate how high the projectile would go?

Given that, can you calculate the energy that is lost due to air resistance?
 
Drawing pictures and listing knowns/unknowns is great help. You know the mass, the height/displacement, and the velocity. These give you the initial kinetic energy and the final potential energy, and the initial energy is always equal to the final energy plus the work done by friction/air resistance/etc (the wasted energy).

It is all pretty straight-forward. ^^
 
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
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