1. 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)-, -, -, 0 d)-, -, +, 0 e)-, +, +, -

2. Velocity Result Which of the following is not a possible correct answer to a velocity transformation problem? a)-0.9 c b)+0.9 c c)+1.2 c d)more than one of the above is impossible

3. 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 v 13 = answer, what are 1 and 3? antiproton and lab b)What, then, is 2? proton c)What are the values of v 12 and v 23 ? -0.9 c and +0.5 c d)Use velocity transformation to get your answer. -0.72c e)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