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 T 0 (spacecraft time) to complete the exam. Show that she should wait a time interval (Earth time) of T = T 0 1 − υ / c 1 + υ / c 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.)
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 T 0 (spacecraft time) to complete the exam. Show that she should wait a time interval (Earth time) of T = T 0 1 − υ / c 1 + υ / c 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.)
Solution Summary: The author explains that the time interval to complete the exam is T_0. Write the equation of dilated time.
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
T
=
T
0
1
−
υ
/
c
1
+
υ
/
c
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.)
2.
1.
Tube Rating
Charts
Name:
Directions: For the given information state if the technique is safe or unsafe and why.
60 Hertz Stator Operation
Effective Focal Spot Size- 0.6 mm
Peak Kilovolts
MA
2
150
140
130
120
110
100
90
80
70
2501
60
50
40
30
.01 .02 .04.06 .1
.2
.4.6 1
8 10
Maximum Exposure Time In Seconds
Is an exposure of 80 kVp, 0.1 second and 200 mA within the limits of the single
phase, 0.6 mm focal spot tube rating chart above?
Is an exposure of 100 kVp, 0.9 second and 150 mA within the limits of the single
phase, 0.6 mm focal spot tube rating chart above?
Q: You have a CO2 laser resonator (λ = 10.6 μm). It has two curved mirrors with
R₁=10m, R2= 8m, and mirror separation /= 5m. Find:
R2-10 m
tl
Z-O
12
R1-8 m
1. Confocal parameter. b= 21w2/2 =√1 (R1-1)(R2-1)(R1+R2-21)/R1+R2-21)
2. Beam waist at t₁ & t2-
3. Waist radius (wo).
4.
5.
The radius of the laser beam outside the resonator and about 0.5m from R₂-
Divergence angle.
6. Radius of curvature for phase front on the mirrors R₁ & R2-
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