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What is the angular momentum of a 3.2-kg uniform cylindrical grinding wheel of radius 25 cm when rotating at 1400 rpm?

a) Determine the linear velocity.
b) Calculate the moment of inertia.
c) Find the angular velocity in rad/s.
d) Identify the torque applied.

User Chayy
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1 Answer

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Final answer:

The angular momentum of a 3.2-kg cylindrical grinding wheel with a 25 cm radius rotating at 1400 rpm is 14.66 kg·m²/s. The moment of inertia is 0.1 kg·m². Assuming no net torque is applied to change the angular velocity, the applied torque would be 0 N·m.

Step-by-step explanation:

To calculate the angular momentum (L) of a rotating cylindrical grinding wheel, you can use the formula L = I⋅ω, where I is the moment of inertia and ω is the angular velocity. For a uniform cylindrical object, the moment of inertia (I) is given by ½MR², where M is the mass and R is the radius. The angular velocity ω in radians per second can be found by converting the rotational speed from revolutions per minute (rpm) to radians per second using the conversion factor 2π radians/rev and 1 minute/60 seconds.

Given a mass (M) of 3.2 kg and radius (R) of 25 cm (0.25 m), and rotational speed of 1400 rpm, first calculate the moment of inertia:

I = 0.5 ⋅ 3.2 kg ⋅ (0.25 m)² = 0.1 kg·m².

Then, convert the angular speed to radians per second:

ω = 1400 rev/min ⋅ (2π radians/rev) ⋅ (1 min/60 s) ≈ 146.61 rad/s.

Finally, calculate the angular momentum:

L = 0.1 kg·m² ⋅ 146.61 rad/s = 14.66 kg·m²/s.

To address the torque, since it is not stated that any external torques are being applied to change the angular velocity, we assume the system is in steady-state rotation, which implies that there is no net torque applied to the system, hence torque would be 0 N·m.

User Raghav Sharma
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