Velocity signs A spaceship is traveling away from Earth toward Planet X. Planet X sends an ambassador ship out to meet them. Take the direction of the spaceship relative to the Earth as positive.

The velocity of the ambassador ship relative to Earth is __; the velocity of the ambassador ship relative to the spaceship is __; the velocity of the spaceship relative to the ambassador ship is __, the velocity of the Earth relative to the ambassador ship is __.

a) -, -, +, +b) +, -, +, -c) -, -, -, 0d) -, -, +, 0e) -, +, +, -

Velocity Result

Which of the following is not a possible correct answer to a velocity transformation problem?

a) -0.9 cb) +0.9 cc) +1.2 cd) more than one of the above is impossible

PAL A proton is traveling at 0.5c relative to the lab. An antiproton is headed for a head-on collision with it, so that it has a speed of 0.9c relative to the proton. To find the velocity of the antiproton relative to the lab, answer these questions:

a) In a sentence, describe your choice of a positive direction.I chose proton relative to lab as + (ok if you chose differently)a) If v13 = answer, what are 1 and 3? antiproton and lab

b) What, then, is 2? protonc) What are the values of v12 and v23? -0.9 c and +0.5 c

d) Use velocity transformation to get your answer. -0.72ce) Do the size and sign of answer make sense? yes - should be

negative (opposite proton rel to lab). should be less than the head-on collision speed of 0.9c and should be less than c