The magnitude of a certain one-dimensional force varies according to:(adsbygoogle = window.adsbygoogle || []).push({});

F = 6.68x^2 + 1.56

where x is the displacement from the origin in meters, and F is the force in Newtons. At t = 0, a 677 g mass is at the origin moving in the positive x-direction at speed 8.46 m/s when this force begins to act on it.

ASSUME: there are no other forces acting on the mass.

a) How much work is done by the force on the mass when it reaches x = 2.78 m?

b) What is the speed of the mass when it reaches 2.78 m?

W=FS

i put x=2.78 into the equation. w=(6.68*2.78^2)*2.78

and get the wrong answer.

3. The attempt at a solution

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# Homework Help: Work and kinetic energy

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