In softball, the pitcher throws with the arm fully extended (straight at the elbow). in a fast pitch the ball leaves the hand with a speed of 139 km/h. find the rotational kinetic energy of the pitcher’s arm given its moment of inertia is 0.720 kg m2 and the ball leaves the hand at a distance of 0.600 m from the pivot at the shoulder.

K.E = 1490.73 J

Explanation:

Given:

Speed of the ball (V)= 139 km/h = 38.61 m/s

Moment of inertia, I = 0.720 kg-m²

Distance, r = 0.600 m

Angular velocity (ω) =

(ω) = =64.35 rad/sec

The kinetic energy (K.E) is given as

K.E =

substituting the values in the above equation we get

K.E =

K.E = 1490.73 J

d) physical means can be used to separate the components of air.

the answer is the first electromagnet (a). this is because it has more coils around the ferromagnetic material. increasing the number of coils increases the surface area in which the metal interacts with the current in the coil. this enables more atoms in the metal to become aligned hence becoming more magnetized.