Is work done by someone catching a moving ball? If someone catches a moving ball with some velocity, then there must be some energy conversion as the ball looses its a kinetic energy. But the ball doesn't move while being caught, and thus does not move in the direction of the force applied by the person's hands. So is the person doing any work?
 A: The person does work taking away the kinetic energy of the ball bringing the ball to a stop. Per the work energy theorem the net work on the ball equals its change in kinetic energy or
$$W_{net}=F_{ave}d=-\frac{mv^2}{2}$$
Where $F_{ave}$ is the average impact force on the person, $d$ is the stopping distance of the ball from the instant of impact to when the person  brings it to a stop, $v$  Is the velocity of the ball on impact, and $m$ is the mass of the ball.
The negative sign means a loss of kinetic energy and that the person has done negative work taking the energy away from the ball and absorbing it in the body increasing its internal energy. Some energy is also absorbed by the ball 
Hope this helps 
A: You can model a catch in 2 ways, in the first you catch the ball and immediately grab it to not let the ball escape. In this case some part of the kinetic energy will dissipate due to the distorsion of the ball (potencial energy) and some part of the energy will dissipate due the sound of the collision.
In the second way you catch the ball while move your arm backwards so you can damp the impact. In this case you done working while you move your arm.  
A: The person is exerting a force on the ball and if you assume the ball to be perfectly rigid,then the centre of mass of the ball should undergo some displacement before coming to rest even if the force exerted by the person is highly impulsive.In a rigid system the displacement of the centre of mass is same as the displacement of the point of application of force(pure translatory motion) and hence the ball is doing work against the external force at the expense of its kinetic energy..
