Select which of the following statements are True or False. Assume Newtonian Mechanics.?
1. T Simple machines can't do any work themselves; they can only transmit the work being applied to them -- perhaps in different form, but not amount. 2. T or F, depending on circumstances This depends on information not given. It is true if the motion is in the same direction as the force; otherwise, it is false. As a categorical statement, it is therefore false. The statement can be repaired thus: "The work done by a constant force acting on an object is equal to the magnitude of the force times the component of the object's displacement along the direction of the force." 3. T Inertial reference frames differ from one another by a constant velocity. Acceleration is the time derivative of velocity. So when finding accelerations of a given body in two inertial frames, you would take the time derivative of both velocities, and they would differ by the time derivative of the velocity difference. And because that velocity difference is constant, its derivative is 0. The result will be equal accelerations in both frames. 4. F Change in kinetic energy is equal to the net work done on it. The former can be 0 only if the latter is also 0. 5. F The work required is its weight (mg) times the distance it is lifted, regardless of the speed. 6. F Power is the (time) rate at which work is done. When applied against a constant force, F, such as gravity, it is equal to that force times the speed, v, of the body. P = Fv So more, not less, power is needed to lift the same body faster. EDIT: The fact that the 4 combinations you tried all came up incorrect, tells me that the correct thing was done by the instructor/system for Q2. Because your 2nd combo matches all the correct answer except for Q2, so it wants "F" for that. My initial fear was that Q2 had been too hastily put together, and was meant to be more carefully stated, in a way that would have made it true (such as my corrected version). But seeing that "F" is the response wanted, means that it was meant just the way it is written.
Select all true statements relating to Special Relativity from those below.?
Select all true statements relating to Special Relativity from those below. A. Adolph Einstein postulated the theory of Special Relativity based on his extensive work conducting laboratory experiments. B. According to Special Relativity (SR), the speed of light is measured the same by any observer, regardless of the motion of the observer. C.There is no absolute or privileged frame of reference in SR. D.A reference frame includes an observer and the instruments he/she uses to measure time, distance, and velocity. E.Because of SR, someone observing a distant frame of reference that is moving at relativistic speeds will see length contract and time dilate (lengthen). F.Two events that are simultaneous in one reference frame will always be observed as simultaneous as seen from another reference frame.
Why is the speed of light independent of the frame of reference and why isn't the rate of passage of time taken as a constant?
The reason for choosing the speed of light as the constant instead of the "rate of change for time" is the definition of reference frame itself. One has to remember that in relativity time is not just a parameter —like in classical mechanics— but a coordinate, an integral part, of the reference frame. The Lorentz transformations tell us how to change from one inertial reference frame to another in the most general case, thus assuming that those reference frames don't share any axis. Saying that "rate of change for time" remains constant is the same as saying that all the reference frames share one of their coordinates, hence they are not different in the strict general case. Now, if one allows all four coordinates to differ, it happens that the speed of light remains constant. Which contains an elegant and beautiful symmetry, as a speed is just the relationship between the spatial and temporal coordinates. So, that the speed of light is constant tell us something deep about inertial reference frames: it tell us the right ratio between their spatial and temporal coordinates.