A heat engine has a cold reservoir of 250°C and a hot reservoir of 715°C. What is the efficienvy of the engine?

A singer raises his pitch one octave. What quality of the sound wave has changed? A.) the speed has increased B.) the amplitude has increased C.) the wavelength has increased D.) the frequency has increased

How many hour are required to make a 3000 km trip if your average speed is 50 km/h?

The right-hand rule predicts which of the following? The direction of the force on a charged object moving in a gravitational field. The direction of the motion of a charged object moving through an electric field.

Which activity is an example of a chemical change? a. sugar dissolving in water b. water evaporating into water wapor c. lighting a match d. freezing water

What are the purposes of a chemical equation?

The gravity of mercury is 3.7 n/kg. Find the mass of an astronaut who weights 241 Newton's on mercury

Why does oxygen have a lower ionization energy than nitrogen?

Traditional Indonesian music uses an ensemble called a gamelan that is based on tuned percussion instruments somewhat like gongs. In Bali, the gongs are often grouped in pairs that are slightly out of tune with each other.

An instrument used to detect a static electric charge is called an ammeter. a. true b. false

A heat engine has a cold reservoir of 250°C and a hot reservoir of 715°C. What is the efficienvy of the engine?