- #1

Neon32

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## Homework Statement

A shaft is turning at 65.0 rad/s at time zero. Thereafter, its angular acceleration is given by α = -10 rad/s 2 - 5t rad/s 3 where t is the elapsed time. (a) Find its angular speed at t = 3.00 s. (b) How far does it turn in the 3.00 s seconds?

t=3 seconds

wi= 65.0 rad/s

α = -10 rad/s 2 - 5t rad/s 3

## Homework Equations

Wf=Wi+αt where α is the angular acceleration

## The Attempt at a Solution

since α = -10 - 5t (1)

at t= 3 seconds

by substitution in (1):

α= -25 rad/s2

From Kinematic equation:

wf=wi+αt

wf=65-25(3)= -10 rad /sI found a different answer in the solutions so please tell me why my answer is incorrect.