6a. Mike travels in an airplane a distance of
840 km. For one-fourth
of the distance, the
airplane flies at a
speed of 960 km/h, and
for the rest of the
distance, it flies at a
speed of 640 km/h.
How long does the trip
take?

The intensity, or loudness, of a sound can be measured in decibels (db), according to the equation , where i is the intensity of a given sound and is the threshold of hearing intensity. what is the intensity, in decibels, [i(db)], when ? use a calculator. round to the nearest whole number. 8 9 19 80

Waves are used in many practical applications to support work, entertainment, and health. one example is the use of ultrasound imaging to safely track the development of a growing fetus. what is a specific example of a practical application of waves in medicine, entertainment, safety, or other fields? provide a brief explanation of how the properties of waves are useful to that application.

If a star is moving toward earth, it is