Asource of sound is detected in the middle of a room. which can account for a decrease in sound intensity for an observer?

a) a decrease in speed from the source

b) an increase in speed from the source

c) a decrease in the radius from the source

d) an increase in the radius from the source

Study the diagram showing the range of temperature in the earth’s layers. which temperature most likely corresponds to the asthenosphere? 1,613°c 2,521°c 3,628°c 6,217°c

If two metal balls each have a charge of -10^-6 c and the repulsive force between them is 1 n, how far apart are they? (coulomb's constant is k = 9.0x 10^9 n-m^2/c^2? 9.5 m 9.0 mm 9.5 cm 0.9 m .

The position of a dragonfly that is flying parallel to the ground is given as a function of time by r⃗ =[2.90m+(0.0900m/s2)t2]i^− (0.0150m/s3)t3j^. a: at what value of t does the velocity vector of the insect make an angle of 34.0 degree clockwise from the x-axis? b: at the time calculated in part (a), what is the magnitude of the acceleration vector of the insect? c : at the time calculated in part (a), what is the direction of the acceleration vector of the insect?