Answer to Question #36228 in Mechanics | Relativity for Rachel

Question

Jack and Jill are standing on a crate at rest on the frictionless, horizontal surface of a frozen pond. Jack has a mass of 75.5kg , Jill has a mass of 44.8kg , and the crate has a mass of 14.4kg . They remember that they must 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 4.40m/s relative to the crate.

Part 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.)


Part B
What is the final speed of the crate if Jack jumps first and then a few seconds later Jill jumps in the same direction?


Part C
What is the final speed of the crate if Jill jumps first and then Jack, again in the same direction?