(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

part a and b are solved(is it correct), but I am not sure how to solve part c.

A single constant force F = (3.02i + 5.45j)N acts on a 3.69kg particle.

a) Calculate the work done by this force if the particle moves from the origin to the point having the vector position r = (1.97i - 2.77j)m

b) What is the speed of the particle at r if its speed at the origin is 3.51m/s?

c)What is the change in the potential energy of the system?

2. Relevant equations

3. The attempt at a solution

a) F dot r = (3.02i + 5.45j) dot (1.97i +-2.77j) = (3.02x1.97)+(5.45x -2.77)= -9.15J

b)1/2mvi^2 - (F dot r) = 1/2mvf^2

(0.5x3.69kgx3.51^2 - 9.15J = 1/2(3.69kg)vf^2

v= 2.71m/s

c)W= Ek-Eg

-9.15J = 1/2mvf2-1/2mvi2 - Eg

-9.15J = 1/2(3.69kg)(2.71^2-3.51^2) - Eg

Eg= 0.033J

can anyone tell me what Im doing wrong for part c?

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# Homework Help: Work and energy (change in potential)

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