The aurora is caused by high natural currents flowing in:

a) the inosphere

b) the upper clouds

c) outer space

d) the asthenosphere

The highest pitched sound that a human ear can detect is about 21 kHz. on the other hand dolphins can hear ultrasound with frequencies up to 280 kHz. what is the speed of sound in water if the wavelength of ultrasound with a frequency of 2.

If the light completed the 71.0-km round trip in the time it took the mirror to complete one-eighth of a revolution, what is the speed of light?

Which one of the following is not a common acid? A. Baking soda B. Vinegar C. Aspirin D. Antiseptic

An electric resistance heater is embedded in a long cylinder of diameter 30 mm. when water with a temperature of 25 c and velocity of 1 m/s flows crosswise over the cylinder, the power per unit length required to maintain the surface at a uniform

Which is not true of atoms

How does the brightness of a bulb tell you about the energy of electrons passing through it?

Why do you think sound travels faster in steel than it does in wood? (Hint: Think about the densities of the two materials, and how the particles might be arranged.)

On which body would a 100kg man have the least gravitational potential energy when lifted to a height of 3 meters

Which of the following factors can negatively affect development? a. Political corruption and instability b. Lack of resources c. Lack of education d. All of the above

A golf ball is hit with an initial velocity of 155 ft/s at an angle of 23 degrees with the horizontal. After 1.4 seconds, how far has the golf ball traveled horizontally and vertically?. a. 199.7 feet horizontally and 75.2 feet vertically. b. 60.