Suppose we had a laser system with a stimulated emission cross section of 10-16 cm2 and an initial inversion of 1014 cm-3 filling a cavity 50 cm long. the cavity uses mirrors with reflectivities r2 = 0.9 (t2 = 0.1) and rl =0.98 (t1 = 0) and contains a nonsaturable loss of 2% per roundtrip. (a) by what factor is the system above threshold (i. e., what is the ratio of δn/δnt)? (b) estimate how long it would take for the laser intensity to increase (from noise) by a factor of 105. (ignore saturation.)

Acatapult is tested by roman legionnaires. they tabulate the results in a papyrus and 2000 years later the archaeological team reads (distances translated into modern units): range = 0.4 km; angle of launch = π/5 rad; landing height = launch height. what is the initial velocity of launch of the boulders if air resistance is negligible?

There is a theory that indicates that dinosaurs became extinct when about 65 million years ago, a large asteroid hit the earth surface. dust caused by this collision blocked the sunlight reaching the earth's surface and many forms of life became extinct due to the cold. fearing this threat, how large the radius of an asteroid should you be looking for if the dangerous asteroid size is approximately the same as the one that killed the dinosaurs? available data suggests that about 18% of that asteroid's mass ended up as a dust spread evenly over earth after eventually settling out of the upper atmosphere. about 0.0180 g/cm^2 of dust, which is chemically different than the earth's rock, covered the earth's surface. typical asteroids have a density of about 1.9 g/cm^3. now that we know the size of the asteroid, how much energy was released during impact, assuming all of it was just the kinetic energy of the asteroid right before the impact?

According to newtons universal law of gravitation, which would change the parh of the ball so it traces out widest curved path possible?