A rotating object has an angular acceleration of α = 0 rad/s2. Which one or more of the following three statements is consistent with a zero angular acceleration?

A. The angular velocity is ω = 0 rad/s at all times.
B. The angular velocity is ω = 10 rad/s at all times.
C. The angular displacement θ has the same value at all times.

Respuesta :

Answer:

A,B and C

Explanation:

Statement A  

At all times, angular velocity is [tex]\omega = 0\,{\rm{rad/s}[/tex]  

Angular acceleration is the rate of change in angular velocity with respect to time.  

Angular velocity and angular acceleration are related by  

[tex]{\omega _{\rm{f}}} = {\omega _{\rm{i}}} + \alpha t[/tex]

Which when re-arranged becomes  

[tex]\alpha = \frac{{{\omega _{\rm{f}}} - {\omega _{\rm{i}}}}}{t}[/tex]

There’s no change in angular velocity anytime when the angular velocity is [tex]\omega = 0\,{\rm{rad/s}}[/tex]

The equation can be modified as follows:  

[tex]\begin{array}{c}\\\alpha = \frac{{0\,{\rm{rad/s}} - 0\,{\rm{rad/s}}}}{t}\\\\ = 0\\\end{array}[/tex]

Therefore, the angular acceleration becomes zero hence statement A is valid.  

Statement B  

Angular acceleration is the rate of change in angular velocity with respect to time.  

Angular velocity and angular acceleration are related by  

[tex]{\omega _{\rm{f}}} = {\omega _{\rm{i}}} + \alpha t[/tex]

Which when re-arranged becomes  

[tex]\alpha = \frac{{{\omega _{\rm{f}}} - {\omega _{\rm{i}}}}}{t}[/tex]

There’s no change in angular velocity anytime when the angular velocity is [tex]\omega = 10\,{\rm{rad/s}}[/tex].The final and initial velocities remain the same.  

The equation can be modified as follows:  

[tex]\begin{array}{c}\\\alpha = \frac{{10\,{\rm{rad/s}} - 10\,{\rm{rad/s}}}}{t}\\\\ = 0\\\end{array}[/tex]

Therefore, the angular acceleration becomes zero and statement B is valid  

Statement C  

Angular velocity is defined as the change in the angular position with respect to time.  

Angular velocity and angular displacement are related by  

[tex]\theta = \omega t[/tex]

Which can also be modified as:  

[tex]{\theta _{\rm{f}}} - {\theta _{\rm{i}}}[/tex]

Note that the final position is [tex]{\theta _{\rm{f}}}[/tex]and initial position is [tex]{\theta _{\rm{i}}}[/tex]

Modifying the equation to find the angular velocity we obtain  

[tex]\omega = \frac{{{\theta _{\rm{f}}} - {\theta _{\rm{i}}}}}{t}[/tex]

When the angular displacement has the same value at all times, the equation becomes  

[tex]\begin{array}{c}\\\omega = \frac{{{\theta _{\rm{i}}} - {\theta _{\rm{i}}}}}{t}\\\\ = 0\\\end{array}[/tex]

The angular velocity becomes zero.  

Angular acceleration and angular velocity are related by  

[tex]{\omega _{\rm{f}}} = {\omega _{\rm{i}}} + \alpha t[/tex]

The expression above can be rearranged as follows:  

[tex]\alpha = \frac{{{\omega _{\rm{f}}} - {\omega _{\rm{i}}}}}{t}[/tex]

At all times, the angular velocity is [tex]\omega = 0\,{\rm{rad/s}}[/tex] hence initial and final velocities remain the same  

We obtain  

[tex]\begin{array}{c}\\\alpha = \frac{{0\,{\rm{rad/s}} - 0\,{\rm{rad/s}}}}{t}\\\\ = 0\\\end{array}[/tex]

Therefore, the angular acceleration becomes zero and statement C is valid.  

Therefore, statements A,B and C are consistent .

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