The court of international trade, because tariffs are taxes upon trade
Blue bounces off the paper
(ff) fortissimo means very loud
1) In the initial situation, the total mechanical energy of the system is given only by the kinetic energy of the ball that is moving with speed v:

where

is the mass of the ball.
In the final situation, where the system (ball+pendulum) rises a vertical distance of h=0.145 m, the system is stationary (v=0) so the total mechanical energy of the system is the gravitational potential energy:

where

is the mass of the pendulum.
For the law of conservation of energy,

, so we can find the initial speed v of the ball:


2) The kinetic energy lost in the collision is the initial kinetic energy of the ball: