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**1. Homework Statement**

As a result of friction, the angular speed of a wheel changes with time according to

d θ/d t = ω_0 e^(−σ t) ,

where ω0 and σ are constants.

initial angular speed = 5.45 rad/s

σ =.23913

Determine the number of revolutions the wheel makes after 2.33 s .

Answer in units of rev.

**3. The Attempt at a Solution**

I know I have to take the integral which is:

θ = - w_0/(σ *e^(-σ *t))

My numbers are initial velocity= 5.45 rad/sec, sigma= .023913, and time=2.33 seconds. so when I solved I got -13.0589 radians and divided it by 2pi to get revolutions, which gave me -2.07839. I thought the answer would be 2.07839 because revolutions can't be negative but it is not right, should i use the negative or am i doing something wrong?