Calculating Angular Acceleration of Horizontal Rod

In summary, a uniform rod with a mass of 2.3 kg and length of 0.32 m can pivot freely about one end. The moment of inertia of the rod about an axis perpendicular to the rod and through the center of mass is given by I = (ml^2)/12. When a 4.6 N force at an angle of 76 degrees to the horizontal acts on the rod, the resulting angular acceleration about the pivot point is approximately 23.287 rad/s^2. However, this answer is incorrect and the parallel axis theorem may need to be used to determine the correct answer.
  • #1
DrunkApple
111
0

Homework Statement


A uniform horizontal rod of mass 2.3 kg and
length 0.32 m is free to pivot about one end
as shown. The moment of inertia of the rod
about an axis perpendicular to the rod and
through the center of mass is given by
I = (ml^2)/12
If a 4.6 N force at an angle of 76 to the hor-
izontal acts on the rod as shown, what is the
magnitude of the resulting angular accelera-
tion about the pivot point? The acceleration
of gravity is 9.8 m/s2 .
Answer in units of rad/s2

Homework Equations


torque = r * F
I = (ml^2)/12
torque = I[itex]\alpha[/itex]

The Attempt at a Solution


I = ml^2/12
=((2.3)(0.32)^2)/12
=0.019626667

torque = r * F
= 0.32 * 4.6sin 76
=1.428275309

torque = I[itex]\alpha[/itex]
1.428275309 = 0.01962667[itex]\alpha[/itex]
[itex]\alpha[/itex]= 72.77216711
a=r[itex]\alpha[/itex]
=72.77216711 * 0.32
=23.28709348
BUT it's wrong...
 

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  • #2
Hint: is the pivot point of the rod located at the center of mass?
 
  • #3
oh do i use parallel axis theorem here?
 

Related to Calculating Angular Acceleration of Horizontal Rod

What is angular acceleration?

Angular acceleration is the rate of change of angular velocity, which is the change in rotational speed of an object. It is measured in radians per second squared (rad/s^2).

How do you calculate angular acceleration?

Angular acceleration can be calculated by dividing the change in angular velocity by the change in time. The formula is: angular acceleration = (final angular velocity - initial angular velocity)/time.

What is the unit of angular acceleration?

The unit of angular acceleration is radians per second squared (rad/s^2). This unit is equivalent to meters per second squared (m/s^2) in linear acceleration.

What is the difference between linear and angular acceleration?

Linear acceleration is the change in velocity of an object in a straight line, while angular acceleration is the change in rotational velocity of an object. Linear acceleration is measured in meters per second squared (m/s^2), while angular acceleration is measured in radians per second squared (rad/s^2).

How does a horizontal rod affect angular acceleration?

A horizontal rod does not affect angular acceleration, as long as the axis of rotation is perpendicular to the rod. This means that the rod is rotating around a fixed point, without any external forces acting on it.

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