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The center of mass of a pitched baseball or radius 4.07 cm moves at 31.3 m/s. The ball spins about an axis through its center of mass with an angular speed of 155 rad/s. Calculate the ratio of the rotational energy to the translational kinetic energy. Treat the ball as a uniform sphere

User Zomega
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1 Answer

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Answer: 0.126

Step-by-step explanation:

To calculate the ratio of the rotational energy to the translational kinetic energy of a baseball, you need to first calculate the rotational energy and the translational kinetic energy of the ball.

The rotational energy of a uniform sphere is given by:

E_rot = (1/2) * I * ω^2

where I is the moment of inertia of the sphere and ω is the angular speed.

The moment of inertia of a uniform sphere of radius r is:

I = (2/5) * m * r^2

where m is the mass of the sphere.

The translational kinetic energy of a moving object is given by:

E_trans = (1/2) * m * v^2

where m is the mass of the object and v is its speed.

Substituting these equations into the expression for the ratio of rotational energy to translational kinetic energy, we get:

(E_rot / E_trans) = [(1/2) * (2/5) * m * r^2 * ω^2] / [(1/2) * m * v^2]

= (2/5) * r^2 * ω^2 / v^2

Plugging in the values for the baseball, we get:

(E_rot / E_trans) = (2/5) * (4.07 cm)^2 * (155 rad/s)^2 / (31.3 m/s)^2

= 0.126

User Juan Castano
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