A heat engine with a high-temperature reservoir at 400 k has an efficiency of 0.20. what is the maximum possible temperature of the cold reservoir?

What best describes the energy in a closed system at the beginning of a day and the energy at the end of the same day? Check all that apply. Some energy can disappear after it has caused motion. Some energy can be changed from one form to another.

Two parallel lines are crossed by a transversal. Parallel lines u and w are cut by transversal t. At the intersection of lines u and t, the bottom left angle is 105 degrees.

A surface is bombarded by particles, each of mass small 'm', which have velocity normal to the surface. On average, n particles strike unit area of the surface each second and rebound elastically. What is the pressure on the surface? A. nmv B.

A car accelerates at 4 m/s2 for 5 seconds. the direction of its acceleration is due east (east = positive direction). if its initial velocity was 7 m/s, also due east, what is its final velocity? round your answer to the nearest meter per second.

Suppose a student takes a study break from astronomy homework and steps out onto his or her balcony on a summer evening. 1. The constellation Cygnus is low in the eastern part of the sky and the 2.

What is the wavelength of an earthquake wave if it has a speed of 5 km/s and a frequency of 10 Hz?

The gamma ray released by each decay carries 140kev of energy. find the total energy e released by decays in the 2 hours.

Think of the last five things you read. Now think of a type of reading you havent done recenty have never read. What kind of pattern do you see in your reading? What is your favorite type of reading and your least favorite type of reading?

Consider this statement: Air is matter. Which facts best support the statement? A. Balloons can be filled with air. B. Air is essential for life to exist. C. Air has mass. D. Air is not an element. E. To float on air is to be happy. F.

Hydroelectric power uses: wind water coal the sun