A grinding wheel of radius 0.370 m rotating on a frictionless axle is brought to rest by applying a constant friction force tangential to its rim. The constant torque produced by this force is 79.2 N • m. Find the magnitude of the friction force.
To find the magnitude of the friction force, we can use the equation:
τ = Fr
where τ is the torque, F is the magnitude of the force, and r is the radius of the wheel.
Given that the torque (τ) is 79.2 N • m and the radius (r) of the wheel is 0.370 m, we can rearrange the equation to solve for F:
F = τ / r
Now we can substitute the given values into the equation to find the magnitude of the friction force:
F = 79.2 N • m / 0.370 m
F ≈ 214.05 N
Therefore, the magnitude of the friction force is approximately 214.05 N.