The uniform seesaw is balanced at its center of mass, as seen below. The smaller boy on the right has a mass of 32.1 kg. What is the mass of his friend (in kg)? F2.0 m -2.0 m→- 4.0 m- kg

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Chapter1: Units, Trigonometry. And Vectors
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**Title: Understanding the Balance of a Seesaw**

The uniform seesaw is balanced at its center of mass, as seen below. The smaller boy on the right has a mass of 32.1 kg. What is the mass of his friend (in kg)?

**Diagram Explanation:**

- The seesaw is depicted as a long plank supported at its midpoint by a triangular fulcrum.
- The left side shows a boy positioned 2.0 meters from the fulcrum.
- The right side shows another boy positioned 4.0 meters from the fulcrum.
- The distance between the fulcrum and each boy is indicated with arrows labeled with their respective distances: 2.0 meters for the boy on the left and 4.0 meters for the boy on the right.

**Objective:**

Calculate the mass of the boy on the left such that the seesaw remains balanced. Enter the answer in the designated box marked in kilograms. 

**Hint:**

Use the principle of moments which states that for the seesaw to be balanced, the moments on either side of the fulcrum must be equal.

\[ \text{Moment on the left} = \text{Moment on the right} \]

Moment is calculated by multiplying the mass by the distance from the fulcrum.
Transcribed Image Text:**Title: Understanding the Balance of a Seesaw** The uniform seesaw is balanced at its center of mass, as seen below. The smaller boy on the right has a mass of 32.1 kg. What is the mass of his friend (in kg)? **Diagram Explanation:** - The seesaw is depicted as a long plank supported at its midpoint by a triangular fulcrum. - The left side shows a boy positioned 2.0 meters from the fulcrum. - The right side shows another boy positioned 4.0 meters from the fulcrum. - The distance between the fulcrum and each boy is indicated with arrows labeled with their respective distances: 2.0 meters for the boy on the left and 4.0 meters for the boy on the right. **Objective:** Calculate the mass of the boy on the left such that the seesaw remains balanced. Enter the answer in the designated box marked in kilograms. **Hint:** Use the principle of moments which states that for the seesaw to be balanced, the moments on either side of the fulcrum must be equal. \[ \text{Moment on the left} = \text{Moment on the right} \] Moment is calculated by multiplying the mass by the distance from the fulcrum.
### Educational Exercise on Angular Momentum

#### Problem (a)
Calculate the angular momentum (in kg·m²/s) of an ice skater spinning at 6.00 rev/s given his moment of inertia is 0.450 kg·m².

\[ \text{Result:} \square \, \text{kg·m²/s} \]

#### Problem (b)
He reduces his rate of spin (his angular velocity) by extending his arms and increasing his moment of inertia. Find the value of his moment of inertia (in kg·m²) if his angular velocity drops to 1.00 rev/s.

\[ \text{Result:} \square \, \text{kg·m²} \]

#### Problem (c)
Suppose instead he keeps his arms in and allows friction with the ice to slow him to 3.00 rev/s. What average torque (in N·m) was exerted if this takes 18.0 seconds?

\[ \text{Result:} \square \, \text{N·m} \]

---
### Notes:
- The questions involve calculating physical quantities related to rotational motion, utilizing concepts like angular momentum, moment of inertia, angular velocity, and torque. 
- Each problem builds upon the previous, demonstrating how changes in physical parameters affect motion.
- This exercise is aimed at students studying physics, specifically rotational dynamics.
Transcribed Image Text:### Educational Exercise on Angular Momentum #### Problem (a) Calculate the angular momentum (in kg·m²/s) of an ice skater spinning at 6.00 rev/s given his moment of inertia is 0.450 kg·m². \[ \text{Result:} \square \, \text{kg·m²/s} \] #### Problem (b) He reduces his rate of spin (his angular velocity) by extending his arms and increasing his moment of inertia. Find the value of his moment of inertia (in kg·m²) if his angular velocity drops to 1.00 rev/s. \[ \text{Result:} \square \, \text{kg·m²} \] #### Problem (c) Suppose instead he keeps his arms in and allows friction with the ice to slow him to 3.00 rev/s. What average torque (in N·m) was exerted if this takes 18.0 seconds? \[ \text{Result:} \square \, \text{N·m} \] --- ### Notes: - The questions involve calculating physical quantities related to rotational motion, utilizing concepts like angular momentum, moment of inertia, angular velocity, and torque. - Each problem builds upon the previous, demonstrating how changes in physical parameters affect motion. - This exercise is aimed at students studying physics, specifically rotational dynamics.
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