Pitching
Positive Work
The baseball has many forces applied upon it. In order to strike out the batter, pitcher's must exert a force on the ball. The speed, spin, and velocity is all controlled by the pitcher. Pitchers use their lower body to build momentum which creates the movement that will release the baseball at a high speed and spin (if applied). You can create negative work by loading and convert it to positive work when delivering the pitch. There is also stored potential energy which is converted to kinetic energy to throw the ball.
A 145g baseball is thrown from rest and released at 75m/s. How much work was performed on the baseball and what did the work?
m=0.145kg
Vi=om/s
Vf=5m/s
W=?
W= ∆ Ek
W=Ek2-Ek1
W=1/2m(Vf*2) -1/2m(Vi*2)
W=1/2 x 0.145kg x 5m/s - 1/2 x 0.145kg x 0m/s
W=0.3625J
W=0.4J
Therefore there was 0.4J of work performed and the person throwing the baseball is doing the work.
m=0.145kg
Vi=om/s
Vf=5m/s
W=?
W= ∆ Ek
W=Ek2-Ek1
W=1/2m(Vf*2) -1/2m(Vi*2)
W=1/2 x 0.145kg x 5m/s - 1/2 x 0.145kg x 0m/s
W=0.3625J
W=0.4J
Therefore there was 0.4J of work performed and the person throwing the baseball is doing the work.
Hitting
Negative Work
The same goes for the hitting components for baseball. In order to hit the ball, your body has to create a force that is applied from the bat to the ball. In order for that to occur your body has to create negative momentum to produce positive momentum which will result in striking the ball with excessive force. This can also be called negative work to positive work. There must also be a change in energy for their to be work. As you load up, you are converting your stored potential energy and changing it to kinetic energy to hit the ball.