Scalar quantity which is the magnitude of velocity.

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2answers
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Sign of Velocity for a Falling Object

I'm working on a homework problem in Mathematica. We have to graph the height and the velocity of a function given an initial height and initial velocity. However, when I do the graph for the velocity ...
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1answer
294 views

Approximate Time Dilation at Rocket Speeds

How do you calculate the time dilation effect experienced by a traveler traveling at a relatively low speed? Specifically, how much time dilation would a traveller moving at $v=0.0007 c$ (speed of ...
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1answer
325 views

speed of light flashlights question

This might be a silly question but I take the risk because it's been puzzling me for quite some time : If you have 2 flashlights, one facing North and one facing South, how fast are the photons (or ...
2
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0answers
211 views

How dangerous is firing a bullet straight up in to the air? [closed]

Question's title says it all how dangerous are the bullets which are fired up straight in to the air? I often find myself in this discussion where there are people who argues that it is harmless and ...
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0answers
112 views

How fast gravity force propagates? [duplicate]

Possible Duplicate: The speed of gravity Lets say for example that a pertubance occured on the Sun that changes its distance to the Earth. How fast we are going to notice the gravity ...
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1answer
182 views

What software can I use to simulate supersonic gas particle flow? [closed]

Please please help me out with this. I am trying to find a software/program that I could use the simulate the scattering effect of light when it strikes gas particles moving at supersonic speeds? ...
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5answers
3k views

Maximum speed of a rocket with a potential of relativistic speeds

Ultimately, the factor limiting the maximum speed of a rocket is: the amount of fuel it carries the speed of ejection of the gases the mass of the rocket the length of the rocket ...
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3answers
469 views

How fast do I need to go in order to avoid being seen by the Police?

I was driving down the road at roughly the speed of traffic. I saw a police officer parked on the side of the road, and also noticed that a Semi was traveling in the lane right next to him. This got ...
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2answers
233 views

Application of mean of speed distribution

Preface The definition of average speed of an object is defined by the distance travelled over time: $$v_{avg} = \frac{x_2 - x_1}{t_2 - t1}$$ The interpretation of speed is that when you multiply ...
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3answers
306 views

Calculating absolute speed of a relative object [closed]

Say you pick a point on the Earth. The earth spins at some constant $x (I don't know how fast, sorry). Now, that point has a different relative speed to a fixed point on Earth's orbit as it revolves ...
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1answer
222 views

What's the highest speed one can obtain safely at home? [closed]

Among common household appliances, things one can make from stuff in the garage or hardware store, and reasonably safe, e.g. within reach of hobbyists and high school kids entering a science fair, ...