A soccer player earned a free goal kick. Sadly, a competitor substituted the normal soccer ball with one partially filled with lead, weighing 30kg. The soccer player managed to kick the ball 20 m having launched it at 45 degrees (Pi/4 radians).
a) what is the initial takeoff velocity of the ball?
b) what is the kinetic energy associated with the take-off velocity?
c) if all of the initial kinetic energy is converted to the potential energy at the top of the arc, how high will the ball go?
d) if all of that foot force was generated by your quadriceps muscles estimate the force required of those muscles. In doing so, you should estimate the mechanical advantage of that joint!