Jack and Jill are standing on a crate at rest on the frictionless horizontal surface of a frozen pond. Jack has mass 80.0 kg, Jill has mass 49.5 kg, and the crate has mass 20.7 kg. They remember that they must go and fetch a pail of water, so each jumps horizontally from the top of the crate. Just after each jumps, that person is moving away from the crate with a speed of 4.04 m/s relative to the crate.

(a) What is the final speed of the crate if both Jack and Jill jump simultaneously and in the same direction? (Hint: Use an inertial coordinate system attached to the ground.)

(a) What is the final speed of the crate if both Jack and Jill jump simultaneously and in the same direction? (Hint: Use an inertial coordinate system attached to the ground.)