A ball is rolled forward at 2 m/s on the floor of a train car. If the train is moving forward at 50 m/s relative to the station platform, i i i f d 50 / l i h i l f what is the velocity of the ball as measured by an observer standing on the platform? g p A. 2 m/s B. 48 m/s C. 50 m/s D. 52 m/s E Not enough information is given E. Not enough information is given.
A pulse of light pointing forward is emitted by a flashlight held b by a person standing in a train car. If the train is moving forward di i i If h i i i f d at 50 m/s relative to the station platform, what is the velocity of the pulse as measured by an observer standing on the platform? p y g p A. 50 m/s B. c - 50 m/s C. c D. c + 50 m/s E Not enough information is given E. Not enough information is given.
Q37.1 As a high-speed spaceship flies past you at half the speed of li h i fi light, it fires a strobe light. An observer on board the spaceship b li h A b b d h hi measures a spherical wave front that spreads away from the strobe light with the same speed c in all directions. The wave g p front that you measure A. is spherical and remains centered on the spaceship as it moves. B. is spherical and is centered on the point where the spaceship was when the strobe was fired. C. is not spherical, but remains centered on the spaceship as it moves. D. is not spherical, but is centered on the point where the spaceship was when the strobe was fired.
Samir, who is standing on the ground, starts his stopwatch at the i instant Maria flies past him in her spaceship at a speed of 0.6 c. M i fli hi i h hi d f 0 6 At the same instant, Maria starts her stopwatch. As measured by Samir, what is the reading on Maria’s stopwatch at the instant g p that his stopwatch reads 10.0 s? A. Less than 10.0 s but more than 0.0 s B. 10.0 s C. More than 10.0 s D. 0.0 s E Not enough information is given E. Not enough information is given.
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