Peoples Physics Concepts

9.1. Kinematics of Rotation http://www.ck12.org

Fc=

mv^2

r

v=

√

Fcr

m

v=

√

50 N∗.5 m

2 kg

v= 3 .53 m/s

Now, we can find the angular speed.

ω=

v

r

ω=

3 .53 m/s

.5 m

ω= 7 .06 rad/s

Now we can begin finding the values asked in the problem based on this information using the equations from the

section above. We’ll start by finding the time before the string breaks.

ω=α∗t

t=

ω

α

t=

7 .1 rad/s

2 rad/s^2

t= 3 .53 s

Lastly, we’ll find the angular displacement of the mass.

ω^2 =ω^2 o+ 2 α∆θ

ω^2 = 0 + 2 α∆θ

∆θ=

ω^2

2 α

∆θ=

( 7 .06 rad/s)^2

2 ∗2 rad/s^2

∆θ= 12 .5 rad

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