Question

in one dimension Mech COnscretion of moment HW-62 3. Two astronauts A and B. narticipate in three collision experiments in a weightless, friction environment. In each experiment, astronaut B is initially at rest, and astronaut A has an initial momentum of 20 kg-m/s to the right. (The velocities of the astronauts are measured with me to a nearby space station.) After Before Experiments 1, 2, and 3 At rest 13. J = 20 kg-m's At rest The astronauts push on each other in different ways so that the outcome of each experiment is different. As shown in the figure at right, astronaut A has a different final momentum in each experiment. a. Determine the magnitude of the final momentum of astronaut B in each experiment. PI = 5 kg-m/s Explain. Bl= 5 kg-m/s b. Rank the three experiments according to the final kinetic energy of astronaut B, from largest to smallest. Explain. C. Is the total kinetic energy after the collision in experiment 2 greater than, less than, or equal to that after the collision in experiment 3? (In this case, total kinetic energy means the sum of the kinetic energies of the two astronauts.) Explain. d. Consider the following statement: "The momentum of the system is conserved in each experiment because there is no net force on the system. If momentum is conserved, then kinetic energy must also be conserved because both momentum and kinetic energy are made up of mass and velocity One of the sentences above is completely correct. Discuss the error(s) in reasoning in the other sentence.

Answer 1

Sinice system is free from external force Velocity in 2nd case, Vasc Balon = 25%m. to its momentum will alloays be Conserved u clochy in Bod moter Case UB: PBron 15/ou before and after collision collie formula for kinetic energy RE - I one Momentum (P) = mass(on) & velocity () (a) Initial momentum , Pi = 2009 mys to i ton remains same for each velocity. Thus whose - velocity high that have righest kinetic energy. for first for second person . VB, VB, UBE person, B. So, K.62> KE-,) kEg / Now consider different situation (1) Trithal momentum / P:) final momentum (P) telefon before Collision for each case st male 20 = 0 tips, It is the momente son of second person, B. ...Po, = 20 lng anje (C) KE antes Collision for 2nd case akan fKEB PP 20 = -5 + Pen > Momente oy AKO ove because it is - PB2 = 25 kg on/ moving opposite to KE after Collision for Bord Cose a REATREB its previous momentum (J. e. K. Ena Im mg/ before. Collision We can see that K.E. 2 > Kifa - 20 = 5+ PBR (d) Momentum is consued because there is are Pon = 15 kg onls external force, the force exerted by masses on each other is internal force. But due to (b) i velocity (u) i momention (P)/ maes(m. Collision there is deformation in shape exist Velocity in 1st case, Nei = PB. = 20 que to which that may or may not be Qonserved released. This kit may or may not be conseived. + 4 map Pro | 252 40519 1152