News cameras take an overhead picture of a part of a crowd at an outdoor event. journalists then count the number of people in the picture and use the sample to estimate the total number of people in the crowd. this process is an example of
a. random sampling.
b. stratified sampling.
c. systematic random sampling.
d. cluster sampling.

Determine the amount of work done when a crane lifts a 100-n block form 2m above the ground to 6m above the ground

Aballet student who learns with the of his instructor is demonstrating learning.

Ajet plane has a sound level of 120 db at a distance of 60 m. what is the q23. sound level at a distance of 6.0 km? (60)2 (6000)? om solution 80db db, hint: 16x assume ultrasound waves travel through the body of an animal at 1540 q24. m/s. if a 30,000 hz signal were reflected off a portion of a heart which was moving toward the source at 3 m/s, what frequency signal would return to the stationary source? solution 30.117hz