Math Problem Statement
A hollow sphere is attached to the end of a uniform rod. The sphere has a radius of 0.64 m and a mass of 0.40 kg. The rod has a length of 1.20 m and a mass of 0.52 kg. The rod is placed on a fulcrum (pivot) at X = 0.42 m from the left end of the rod.
(a) Calculate the moment of inertia (click for graphical table) of the contraption around the fulcrum. kg m2
(b) Calculate the torque about the fulcrum, using CCW as positive. N m
(c) Calculate the angular acceleration of the contraption, using CCW as positive. rad/s2
(d) Calculate the linear acceleration of the right end of the rod, using up as positive. m/s2
Solution
Let's calculate each part of the problem step by step:
Given:
- Radius of sphere
- Mass of sphere
- Length of rod
- Mass of rod
- Pivot distance
- Acceleration due to gravity
(a) Moment of Inertia
-
For the rod: where is the moment of inertia about its center, and the second term accounts for the distance from the pivot (parallel axis theorem).
-
For the hollow sphere: The moment of inertia of the hollow sphere about its center is: Using the parallel axis theorem to shift the axis to the pivot (which is at a distance from the center of the sphere):
Adding the contributions from both the rod and the sphere: Result:
(b) Torque about the Fulcrum
Torque is calculated as . In this case, the force is the weight due to gravity, and since the forces are vertical, .
-
Torque due to the rod: The center of mass of the rod is at , so:
-
Torque due to the sphere: The force due to the sphere acts at distance from the pivot:
Summing both torques: Result:
(c) Angular Acceleration
Using Newton's second law for rotation, the angular acceleration is: Substituting the values for torque and moment of inertia:
(d) Linear Acceleration of the Right End of the Rod
The linear acceleration of the right end of the rod is related to the angular acceleration by: Substituting the angular acceleration and length of the rod:
Final Results:
- (a) Moment of inertia:
- **(b)
Ask a new question for Free
By Image
Drop file here or Click Here to upload
Math Problem Analysis
Mathematical Concepts
Moment of inertia
Torque
Angular acceleration
Linear acceleration
Formulas
I_rod = (1/12) * m_rod * L^2 + m_rod * X^2
I_sphere = (2/3) * m_sphere * R^2 + m_sphere * (L - X)^2
Torque (τ) = r * F * sin(θ)
Angular acceleration (α) = τ / I_total
Linear acceleration (a) = α * L
Theorems
Parallel axis theorem
Newton's second law of motion for rotation
Suitable Grade Level
Undergraduate Physics
Related Recommendation
Calculate Angular Acceleration of Thin-Walled Hollow Sphere with Given Torque
Rotational Motion of a Rod with Attached Masses - Moment of Inertia, Torque, and Angular Acceleration
Determine Equilibrium and Angular Acceleration in a Rotational Dynamics Problem
Calculate Angular Acceleration of a Rotating Rod with Attached Masses
Calculating Moment of Inertia and Tangential Velocity for a Swinging Rod