Calculating the Net Force Acting on a 2.75 kg Object

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Homework Help Overview

The discussion revolves around calculating the net force acting on a 2.75 kg object moving in a plane, with its position described by specific equations for x and y coordinates over time. Participants are attempting to derive the net force using the relationship between force, mass, and acceleration.

Discussion Character

  • Exploratory, Mathematical reasoning, Problem interpretation

Approaches and Questions Raised

  • Participants discuss taking the second derivative of the position equations to find acceleration, followed by applying Newton's second law (F=ma) to calculate the force. There are questions about the correctness of calculations and potential arithmetic errors.

Discussion Status

Some participants have shared their calculated values for the net force, but there appears to be a discrepancy in the results, leading to further questioning of the calculations and methods used. Guidance has been offered, but no consensus on the correct approach or answer has been reached.

Contextual Notes

One participant mentions that their calculated answer was marked incorrect by an online submission program, indicating potential issues with the approach or calculations. There is an emphasis on ensuring accuracy in arithmetic and method application.

tarzanna
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Homework Statement



A 2.75 kg object is moving in a plane, with its x and y coordinates given by x = 7t^2 - 4 and y = 5t^3 + 1, where x and y are in meters and t is in seconds. Find the magnitude of the net force acting on this object at t = 2.35 s.

Homework Equations



F=ma

The Attempt at a Solution



I took the 2nd derivative of each posn eqn and then substituted 2.35s for t to get accel; multiplied each accel by 2.75 kg to get Fx and Fy; then took the sqrt of (Fx^2 + Fy^2) to get magnitude.

I am not sure how to proceed. Thanks for any help!
 
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Write the answer down and turn the question in, you already got it.
 
Thanks. I calculated the answer to be 104.5 N but it was marked as incorrect by the web program I use to turn in assignments. So something isn't right.
 
I got 198 N, you must've made an arithmetic error.
 

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