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[SOLVED] Torque & Angular Speed
The wheel of an engine has a moment of inertia 2.80kgm^2 about its rotation axis.
What constant torque is required to bring it up to an angular speed of 360 rev/min in a time of 7.60 s, starting from rest?
What is its final kinetic energy?
torque = rF sin(theta)
k=.5mv^2
First I converted 360 rev/min to seconds
so
360 (rev/min) ( 1 min/60s)( 2pi/rev) = 37.699 rad/s
t = 7.60
I = 2.80 kgm^2
so I decided to get angular acceleration, in case I need it is
alpha = 4.96
From what I spotted in my book Sum of torque = I(angular acceleration)
torque = (2.80)(4.96)
torque = 13.89
this is right, but is they way I have done it correct or did I just get lucky. I am afraid I just plugged into the "sum of torquez = I (angular accelerationz)"
without understanding it :O
part two of the question is
What is its final kinetic energy?
for this
K=.5mv^2
how do I implement this into the problem if I don't have mass?
omega = omega initial + alpha(time)
Homework Statement
The wheel of an engine has a moment of inertia 2.80kgm^2 about its rotation axis.
What constant torque is required to bring it up to an angular speed of 360 rev/min in a time of 7.60 s, starting from rest?
What is its final kinetic energy?
Homework Equations
torque = rF sin(theta)
k=.5mv^2
The Attempt at a Solution
First I converted 360 rev/min to seconds
so
360 (rev/min) ( 1 min/60s)( 2pi/rev) = 37.699 rad/s
t = 7.60
I = 2.80 kgm^2
so I decided to get angular acceleration, in case I need it is
alpha = 4.96
From what I spotted in my book Sum of torque = I(angular acceleration)
torque = (2.80)(4.96)
torque = 13.89
this is right, but is they way I have done it correct or did I just get lucky. I am afraid I just plugged into the "sum of torquez = I (angular accelerationz)"
without understanding it :O
part two of the question is
What is its final kinetic energy?
for this
K=.5mv^2
how do I implement this into the problem if I don't have mass?
omega = omega initial + alpha(time)