A physics professor on the Earth gives an exam to her students, who are in a spacecraft traveling at speed v relative to the Earth. The moment the craft passes the professor, she signals the start of the exam. She wishes her students to have a time interval T0 (spacecraft time) to complete the exam. Show that she should wait a time interval (Earth time) of
before sending a light signal telling them to stop. (Suggestion: Remember that it takes some time for the second light signal to travel from the professor to the students.)
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EBK PHYSICS FOR SCIENTISTS AND ENGINEER
- According to special relativity, a particle of rest mass m0 accelerated in one dimension by a force F obeys the equation of motion dp/dt = F. Here p = m0v/(1 –v2/c2)1/2 is the relativistic momentum, which reduces to m0v for v2/c2 << 1. (a) For the case of constant F and initial conditions x(0) = 0 = v(0), find x(t) and v(t). (b) Sketch your result for v(t). (c) Suppose that F/m0 = 10 m/s2 ( ≈ g on Earth). How much time is required for the particle to reach half the speed of light and of 99% the speed of light?arrow_forwardThe Sun produces energy at a rate of 4.001026 W by the fusion of hydrogen. (a) How many kilograms of hydrogen undergo fusion each second? (b) If the Sun is 90.0% hydrogen and half of this can undergo fusion before the Sun changes character, how long could it produce energy at its current rate? (c) How many kilograms of mass is the Sun losing per second? (d) What fraction of its mass will it have lost in the time found in part (b)?arrow_forwardPlaying a high-stakes game of basketball with a series of cartoon characters. The court has a total length of 28 meters measured in its own rest frame. The Street Sprinter, an animated lion on your team, can run at a maximum speed of ½ c. As measured in the rest frame of the court, a player on the opposing side throws a ball at ¼c from half court. At the same time, the Street Sprinter starts running at full speed from the full length of the court away. Call this time t=0. Draw a Space-Time diagram from the rest frame of the court with the Street Sprinter's initial position as the origin. Mark the following events on it, and find their spacetime coordinates (t,x) in the frame of the court and (t',x') in the frame of the Street Sprinter: A: The ball is thrown from half-court. B: The Street Sprinter takes off from the other side of the court C: The ball reaches the net D: The Street Sprinter reaches the net e) From the perspective of the referee in the court rest frame, does the ball…arrow_forward
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