Calculating Force Needed to Accelerate a 7.00g Pellet from Rest to 175 m/s

AI Thread Summary
To calculate the average force needed to accelerate a 7.00-gram pellet to 175 m/s over 0.700 m, the correct mass in kilograms is 0.007 kg, leading to a force of 875 N after applying the formula F=ma. For the fisherman scenario, a force diagram is recommended to analyze the situation, considering the line's test value of 22 N indicates the maximum force it can withstand before snapping. In the baseball example, the average force applied by the ball on the glove can be determined similarly to the pellet calculation, using the mass and deceleration over the distance of 11.0 cm. The discussions emphasize the importance of unit conversion and proper application of physics formulas. Understanding these principles is crucial for solving similar problems effectively.
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8. What average force is needed to accelerate a 7.00-gram pellet from rest to 175 m/s over a distance of 0.700 m along the barrel of a rifle?

9. A fisherman yanks a fish out of the water with an acceleration of 4.5 m/s^2 using very light fishing line that has a "test" value of 22 N. The fisherman unfortunately loses the fish as the line snaps. What can you say about the mass of the fish?

10. A 0.140-kg baseball traveling 45.0 m/s strikes the catcher's mitt, which, in bringing the ball to rest, recoils backward 11.0 cm. What was the average force applied by the ball on the glove?3

I tried doing number 8 on my own.

vfinal^2=vinitial^2 + 2ad
175m/s=0^2 + 2a(0.700m)
a= 125m/s
F=ma
F=(7.00g)(125 m/s)
F=875N

Is this correct>? How do you do the others?
 
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You did 8 correct all the way to the last part, since you use MKS units, you need the mass in kilograms, 7 grams = 0.007kg.

Draw a force diagram for 9, should be all you need. Assume he pulsl the fish straight up

10 is done the same way as 8
 
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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