A fighter plane at sea is landing upon an aircraft carrier deck. When the aircraft lands, it must 'catch' a restraining elastic line in order to come to a halt. If the 12,000 kg aircraft has a landing speed of 70 meters/sec and must be brought to a halt in 120 meters, what is the magnitude of the K for the restraining line?

Aspring is used to stop a 50-kg package which is moving down a 20º incline. the spring has a constant k = 30 kn/m and is held by cables so that it is initially compressed 50 mm. knowing that the velocity of the package is 2 m/s when it is 8 m from the spring and neglecting friction, determine the maximum additional deformation of the spring in bringing the package to rest.