A volleyball player is jumping up to spike (hit) a ball. Des…

A volleyball player is jumping up to spike (hit) a ball. Describe the work produced by the muscle at the knee joint during the take-off. Make sure to include the primary muscle responsible for producing the work, the type of muscle contraction occurred, and the effect of work on the total mechanical energy of the player’s body.  Make sure to provide your answer in complete sentences and explain your answer clearly to receive a full credit. 

A mass M is connected to a spring with constant Ks and a dam…

A mass M is connected to a spring with constant Ks and a damper with constant Kd, and is moving with displacement x with friction Kf. Assume the input if the force f. Find the model of the following mass-spring-damper systems in the state space (find the matrices A).