Acircular window 30 cm in diameter in a submarine can withstand a maximum force, exerted by the fluids surrounding it, of 5.20 × 105 n without damage. what is the maximum depth in a fresh-water lake to which the submarine, containing air at atmospheric pressure, can go without damaging the window? the density of fresh water is 1000 kg/m3.

Scientists use laser range-finding to measure the distance to the moon with great accuracy. a brief laser pulse is fired at the moon, then the time interval is measured until the "echo" is seen by a telescope. a laser beam spreads out as it travels because it diffracts through a circular exit as it leaves the laser. in order for the reflected light to be bright enough to detect, the laser spot on the moon must be no more than 1.0 km in diameter. staying within this diameter is accomplished by using a special large-diameter laser. part a if λ = 540nm , what is the minimum diameter of the circular opening from which the laser beam emerges? the earth-moon distance is 384,000 km. express your answer to two significant figures and include the appropriate units.

In a system, when potential energy decreases, then entropy also decreases. true false

An owl dives toward the ground with a constant velocity of 4.40 m/s at 53.0° below the horizontal. the sun is directly overhead and casts a shadow of the owl directly below it. what is the speed (in m/s) of its shadow on level ground?