Questions from Modern Physics

Q: An airplane has a length of 60 m when measured at rest

An airplane has a length of 60 m when measured at rest. When the airplane is moving at 180 m/s (400 mph) in the alternate universe, how long would the plane appear to be to a stationary observer? a....

Q: If the airplane of Passage Problem 37.71 has a rest

If the airplane of Passage Problem 37.71 has a rest mass of 20,000 kg, what is its relativistic mass when the plane is moving at 180 m/s ? a. 8000 kg; b. 12,000 kg; c. 16,000 kg; d. 25,000 kg; e....

Q: In the alternate universe, how fast must an object be moving

In the alternate universe, how fast must an object be moving for it to have a kinetic energy equal to its rest mass? a. 225 m/s; b. 260 m/s; c. 300 m/s; d. The kinetic energy could not be equal to...

Q: A cube of metal with sides of length a sits at rest

A cube of metal with sides of length a sits at rest in a frame S with one edge parallel to the x-axis. Therefore, in S the cube has volume a3. Frame S′ moves along the x-axis with a speed u. As measur...

Q: A space probe is sent to the vicinity of the star Capella

A space probe is sent to the vicinity of the star Capella, which is 42.2 light-years from the earth. (A light-year is the distance light travels in a year.) The probe travels with a speed of 0.9930c....

Q: A muon is created 55.0 km above the surface of

A muon is created 55.0 km above the surface of the earth (as measured in the earth’s frame). The average lifetime of a muon, measured in its own rest frame, is 2.20 µs, and the muon we are considering...

Q: The net force F on a particle of mass m is directed

The net force F on a particle of mass m is directed at 30.0° counterclockwise from the +x-axis. At one instant of time, the particle is traveling in the +x-direction with a speed (measured relative to...

Q: Two atomic clocks are carefully synchronized. One remains in New York

Two atomic clocks are carefully synchronized. One remains in New York, and the other is loaded on an airliner that travels at an average speed of 250 m/s and then returns to New York. When the plane r...

Q: The distance to a particular star, as measured in the earth’s

The distance to a particular star, as measured in the earth’s frame of reference, is 7.11 light-years (1 light-year is the distance that light travels in 1 y). A spaceship leaves the earth and takes 3...

Q: In the earth’s rest frame, two protons are moving away from

In the earth’s rest frame, two protons are moving away from each other at equal speed. In the frame of each proton, the other proton has a speed of 0.700c. What does an observer in the rest frame of t...