Feynman diagrams (a) draw both a scattering and an annihilation tree-level feynman diagram for the interaction ? +? - labelling them accordingly . in each diagram label all particles, including the propagator, and initial and final states (b) state what prevents the ? +? - interaction from having both a scattering and an annihilation diagram.

Choose the most likely outcome of this scenario: jen decided to go bike riding without a helmet. while no one is around during her ride, she is thrown from her bike when her wheel goes into a pothole. she is not injured, but she is terrified to get back on her bike. what happens next? a. her physical health is affected even though she wasn't hurt. b. her mental and emotional health are affected because she is afraid to get back on her bike. c. her social health is affected because she is worried her friends saw the fall. d. her overall health is not affected at all by her fall.

You've already seen the value of 9.8 in this lesson. what's this value called? what quantity does it represent?

On mars a rock falls an unknown vertical distance from a resting position and lands in a crater. if it takes the rock 2.5 seconds to fall, how high is the cliff the rock fell from? mars' surface gravity is 3.8 m/s2. a. 9.5 m b. 11.9 m c. 15.2 m d. 23.8 m