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How to Calculate Angular Acceleration from Force

Angular Acceleration Formula:

\[ \alpha = \frac{\tau}{I} = \frac{r \times F}{I} \]

N
m
kg·m²

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1. What is Angular Acceleration?

Angular acceleration (α) is the rate of change of angular velocity with respect to time. It describes how quickly an object's rotational speed is changing. The formula relates torque (τ), moment of inertia (I), and angular acceleration through Newton's second law for rotation.

2. How Does the Calculator Work?

The calculator uses the angular acceleration formula:

\[ \alpha = \frac{\tau}{I} = \frac{r \times F}{I} \]

Where:

Explanation: This equation represents Newton's second law for rotational motion, where torque is the rotational equivalent of force, and moment of inertia is the rotational equivalent of mass.

3. Importance of Angular Acceleration Calculation

Details: Calculating angular acceleration is essential in mechanical engineering, robotics, vehicle dynamics, and any system involving rotational motion. It helps determine how quickly objects can start or stop rotating, which is crucial for designing motors, gears, and rotating machinery.

4. Using the Calculator

Tips: Enter force in newtons (N), radius in meters (m), and moment of inertia in kg·m². All values must be positive numbers. The calculator will compute the angular acceleration in radians per second squared (rad/s²).

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between linear and angular acceleration?
A: Linear acceleration measures change in linear velocity (m/s²), while angular acceleration measures change in rotational speed (rad/s²). They are related through the radius: a = α × r.

Q2: How do I calculate moment of inertia?
A: Moment of inertia depends on the object's mass distribution. For common shapes: solid cylinder I = ½mr², hollow cylinder I = mr², sphere I = ⅖mr², where m is mass and r is radius.

Q3: What factors affect angular acceleration?
A: Angular acceleration increases with greater force or longer lever arm, and decreases with larger moment of inertia. Friction and other resistive torques also affect the net acceleration.

Q4: Can angular acceleration be negative?
A: Yes, negative angular acceleration indicates deceleration or rotation in the opposite direction to the initial angular velocity.

Q5: What are typical units for angular acceleration?
A: The SI unit is radians per second squared (rad/s²). Other units include degrees per second squared (°/s²) and revolutions per second squared (rev/s²).

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