Physics 35 questions – Flashcards

61 km/h

A lot! Relative to the Sun, it is nearly 110,000 km/hr. And the Sun is not at rest; it orbits the center of the galaxy, which moves with respect to other galaxies.

The length of the material in the experiment contracted in the direction of motion. (by just the amount required to counteract the presumed variation in the speed of light.) The needed "shrinkage factor" was worked out by Hendrik Lorentz.

Einstein rejected the idea that space and time are independent.

All laws of nature in all uniformly moving frames of reference

The speed of light in a vacuum

The distances traveled by light are the same.

The distance travelled by light to the back is shorter.

Usually three axes used to describe three-dimensional space. Coordinate axes x, y, z of the reference frame specify the position of any location in space. The fourth dimension measures time.

We experience the same spacetime when we are in the same frame of reference with zero velocity relative to each other.

The ratio is always the same, the speed of light.

It takes longer.

Time dilation

1/(1 - v 2/c 2)1/2; v 2/c 2 is always a positive number, so the denominator is less than 1, making the ratio greater than 1.

For 0.50c, time dilates to 1.15 times the proper time. For 0.995c, time dilates to 10 times the proper time.

Atomic clocks in orbit in the GPS system run slower because they are in orbit. Short-lived particles travelling at high speeds in particle accelerators live longer. Atomic clocks flown in jets run slower because they are in motion.

The frequency increases.

Only frequency increases.

Twice as long

Stay-at-home, 1; traveler, 2 (separated by the acceleration of the spaceship in turning around)

Maximum 1, minimum 0

Yes. If either v1 or v2 is equal to c, then V = c.

The large quantity of energy needed and radiation shielding

There is none.

1/10 m

1 m. No contraction takes place vertically when an object is moving horizontally. Contraction takes place only in the direction of motion!

No. The stick is in your frame of reference.

The momentum would be infinite. pg 677

The radius of curvature when subjected to a sideways force is greater.

In a single reaction, nuclear reactions release more than a million times the energy of chemical reactions. But, in releasing the same total amount of energy, the same amount of mass is lost in both types of reactions.

Fissioning one uranium nucleus produces 10 million times more energy than the combustion of one carbon atom.

All three!

Energy is mass and c2 is the conversion factor for the units.

At everyday low velocities, relativistic equations approach the Newtonian equations.

They hold true but the differences they predict are hard to measure. In Quantum Mechanics, the correspondence principle is that for large quantum numbers (large energies) the classical limit is reached. Likewise, in relativity, the correspondence principle is that for slow speeds relative to the velocity of light, classical mechanics is recovered (as it should!).

Assuming that there are no vibrations etc to indicate motion and assuming that the observer becomes conscious of being in the train only after uniform motion is underway - as would happen if the observer were to awake from deep slumber after the train had achieved uniform motion. The sense of motion can only be conveyed if there are vibrations or acceleration/deceleration in any direction.

If the sweep rate were made to be faster than 30 cm per nanosecond, ( 0.033 nanoSec per cm ). The actual electrons in the beam, will be traveling at less than the speed of light. Another example is if you take a laser and shine it on a little cube shaped mirror, and spin the mirror at thousands of RPM, and the light from the mirror is directed toward the moon. The line of light that impacts the moon will appear to travel across the surface at a speed that may exceed the speed of light. But its kind of an illusion. No 'thing' is actually traveling faster than light. You cannot interrupt the light at one point on the surface and have any information travel to another point on the surface at super luminal speed. No actual matter, energy, or information is travelling faster than the speed of light.

the speed of light is not infinite. As a result, there will be a time difference between when an event happens, and when the light containing the information about the event reaches different points in space at different distances from the event.