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During takeoff, the sound intensity level of a jet engine is 170 dB
dB at a distance of 32 m
m . What is the sound intensity level at a distance of 1.0 km
km?
The centers of two masses are 5m apart. The masses exert a gravitational force of
2.4x10^-4 N on each other. Find the masses if one is three times the mass of the other.
A child is in a bouncy swing suspended from a spring. If the spring stretches 15cm when
the8.5 kg child is put in it, what is its spring constant? How much time does it take for the
child to complete one bounce?
What is the speed of a satellite moving in a circular orbit at a height of 3800km above
the surface of the earth? (b) what is the period of the satellite in hours? The mass of the
earth is 5.97x10^24 kg. The radius of the earth is 6.38x10^6 m.
Find the wavelength in air at 20°C of an 18-Hz sound wave, which is one of the lowest frequencies that is detectable by the human ear
surface of the earth? (b) what is the period of the satellite in hours? The mass of the
earth is 5.97x10^24 kg. The radius of the earth is 6.38x10^6 m
Two blocks with different masses are attached to either end of a light rope that passes over a light, frictionless pulley suspended from the ceiling. The masses are released from rest, and the more massive one starts to descend. After this block has descended 1.20 𝑚, its speed is 3.00 𝑚/𝑠. If the total mass of the two blocks is 22.0 𝑘𝑔, what is the mass of each block?
A 62.0-𝑘𝑔 skier is moving at 6.50 𝑚/𝑠 on a frictionless, horizontal, snow-covered plateau when she encounters a rough patch 4.20 𝑚 long. The coefficient of kinetic friction between this patch and her skis is 0.300. After crossing the rough patch and returning to friction-free snow, she skis down an icy, frictionless hill 2.50 𝑚 high. (a) How fast is the skier moving when she gets to the bottom of the hill? (b) How much internal energy was generated in crossing the rough patch?
