George walks to a friend's house. He walks 750 meters North then realizes he walked too far. He turns around and walks 250 meters south. The entire walk takes him 13 seconds. What is his speed per second?

Which of the following observations demonstrates the differences between speed of light and speed of sound? (Note, they are all true, but which one represents the difference in the speed?)) A.

Words that describe direction east, up, and left is it true or false

A carnot engine operates between two heat reservoirs at temperatures th and tc. an inventor proposes to increase the efficiency by running one engine between th and an intermediate temperature t and a second engine between t and tc using as input

When sinkholes expand, creating isolated towers of rock, what is occurring? A. Rainwater is becoming more acidic B. Mature karst topography is being eroded C. Young karst topography is evolving into mature karst topography D.

Suppose you exert a 400-N force on a wall but the wall does not move. The work you are doing on the wall is : unknown, because the mass of the wall is not given zero, because the wall is not moving 3920 J 400 J

Why is coal costly to produce? 1. coal is found deep underground. 2. Coal is expensive to make 3. Coal is only found in certain places on earth. 4. Coal is difficult to make in the lab.

Karen has a mass of 51.9 kg as she rides the up escalator at Woodley Park Station of the Washington D. C. Metro. Karen rode a distance of 63.1 m, the longest escalator in the free world. The acceleration of gravity is 9.8 m/s 2.

What is the current in a 160V circuit if the resistance is 2Ω?

A thermometer is placed in water in order to measure the water's temperature. What would cause the liquid in the thermometer to drop? A. The molecules in the water spread apart. B. The molecules in the thermometer's liquid spread apart. C.

The amount of energy carried by a wave is proportional to the square of the wave's A. frequency B. amplitude C. wavelength D. period ... ?