An astronomical telescope has an objective of diameter 20 cm with a focal length of 180 cm. the telescope is used with an eyepiece of focal length 30 mm. what is the angular magnification of this telescope?

A boy throws a ball up into the air with a speed of 12.3 m/s. The ball has a mass of 0.25 kg. How much gravitational potential energy will the ball have at the top of its flight? (Assume there is no air resistance.) A. 13,5 J B. 20.23 C. 18.9 J D.

Identify the element that has nine protons

A city located on the coast of North America has warmer winters and cooler summers than a city at the same elevation and latitude located near the center of North America.

1The Drifting Rocks are a strange phenomenon still unexplained by science. 2Located in Death Valley, California, the rocks sit on hot, flat ground. 3Unlike normal rocks, they have trails etched behind them as if they have traveled across the sand.

How to start my introduction in science about the history of matter?

A resistor has a current of 2 amperes when connected to a single battery. If a second identical battery is connected in series with the first, what is the current through the resistor? a) Still 2 amps b) 4 amps c) 1 amp d) no current

Describe some basic guidelines for safe PRE

Why is the liver important in digestion

A building 190 feet tall casts a 30 foot long shadow. if a person stands at the end of the shadow and looks up to the top of the building, what is the angle of the person's eyes to the top of the building (to the nearest hundredth of a degree) ?

The frequency of which type of electromagnetic wave is just higher than that of visible light? A. infrared waves B. gamma rays C. x-rays D. radio waves E. ultraviolet rays