Two systems k and k’ synchronize their clocks at t = t’ = 0 when their origins are aligned as system k’ passes by system k along the x axis at relative speed 0.8c. at time t = 3 ns, frank (in system k) shoots a proton gun having proton speeds of 0.98c along his x axis. the protons leave the gun at x = 1 m and arrive at a target 120 m away. determine the event coordinates (x, t) of the gun firing and of the protons arriving as measured by observers in both systems k and k’.

Athin, square metal plate measures 14 cm on each side and has emissivity of 0.60. the plate is heated to a temperature of 745°c. what is the rate at which the plate radiates energy ? the stefan-boltzmann constant is 5.67 × 10-8 w/(m2 ? k4). remember that the plate will radiate energy from both its top and bottom surfaces.

Wo small variable-thrust jets are actuated to keep the spacecraft angular velocity about the z-axis constant at ? 0 = 1.16 rad/s as the two telescoping booms are extended from r1 = 1.18 m to r2 = 4.69 m at a constant rate over a period of 124 seconds. the small 19-kg experiment modules at the ends of the booms may be treated as particles, and the mass of the rigid booms is negligible. determine the necessary thrust t for each jet as a function of time where t = 0 is the time when the telescoping action is begun. after you have the general expression for t, answer the questions. show work.

Takumi works in his yard for 45 minutes each saturday. he works in the morning, and he wears sunscreen and a hat each time he works in the yard. what does takumi hope to reduce through his actions? the likelihood of stochastic effects, such as dna mutations the severity of stochastic effects, such as cancer the severity of non-stochastic effects, such as cancer the likelihood of non-stochastic effects, such as radiation sickness