- #1

kjamha

- 98

- 1

## Homework Statement

The position of an object of mass 2 kg is changing as a function of time by the formula x(t) = 4t^3-6t. (a) find the work done by the forces acting on the particle between t=1 and t=3s. (b) What is the object's velocity when the force on it is zero?

## Homework Equations

is my work for part (a) correct?

I do not know how to approach b.

## The Attempt at a Solution

I took the derivative of the equation

12(t)^2 - 6 at t=1s and t=3s

to find vi and vf (I have vi = 6 m/s and vf = 102 m/s).

Then I used W = change in KE

1/2 x 2(102^2) - 1/2 x 2 (6^2) = 10,368 J.

Is that correct?

I'm not sure how to start part b