- #1

nickclarson

- 32

- 0

**[SOLVED] Please help: A box on a frictionless plane, find the power based on work and**

## Homework Statement

A box of mass M = 7.68 kg is at rest at the bottom of a frictionless inclined plane.

The box is attached to a string that pulls with a constant tension T = 113 N. Write the general equation that gives the work done by the tension when the box has moved a distance x along the plane. Now, find the speed of the box as a function of x and the angle of the plane. Finally, for a distance of x = 6.38 m and an angle of 30.5°, determine the power delivered by the tension in the string as a function of x.

## Homework Equations

[tex]K=\frac{1}{2}mv^{2}[/tex]

[tex]P=FV[/tex]

## The Attempt at a Solution

I know I am supposed to multiply the net force by velocity for the last part, but I need to find the velocity.

I figured I could use kinetic energy to find the velocity using the ke work theorem. So...

[tex]KE_{f}-KE_{i}=W[/tex]

And since the initial energy is 0

[tex]KE_{f}=W[/tex]

Am I on the right track?

----------------------

Edit: Solved

Here's the final equation I derived:

[tex]P=T\sqrt{\frac{2x(T-mgsin\theta)}{m}}[/tex]

Last edited: