# Angular Acceleration of Electric Motor

## Homework Statement

An electric motor starts from rest at time t=0. Its angular velocity is: w=100t-4t3

A) If the angle of rotation, x, of the motor is also zero when t=o, determine an expression for this angle in terms of t.

## The Attempt at a Solution

For A) I thought you just integrate the expression given for angular velocity so i got x=50t^2-t^4.

For B), I said that x=2pi, so 2pi=50t^2-t^4 but I am unsure how to solve this for x.

Any help much apriciated,

Mike

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rock.freak667
Homework Helper
For B), I said that x=2pi, so 2pi=50t^2-t^4 but I am unsure how to solve this for x.
if y=t2, then your equation becomes:

2π=50y-y2

I think you can solve for 'y' now and then find 't'

Clever!

Thanks alot!

Mike