How did people years ago find out which side of a magnet was north and which was south?

A string vibrates at a frequency of 20hz what is its period

Which involves reflection of light waves? A. A full moon shows sunlight bouncing off the moon's surface and traveling toward Earth. B. Ultraviolet waves of energy are taken in by sunburned skin ... C.

Technician A says that when a fuse has popped, it just needs to be replaced, since it performed its job. Technician B says that when a fuse has blown, the circuit needs to be diagnosed because the fuse was probably not the problem. Who is correct? A.

If you drag an object of 20 newtons force with a rope through a distance of 3 meters, you have done? on-meters of work. a. 60 b. 30 c. 16

How many nanoseconds are there in 1.90 yr? Express your answer using three significant figures.

Inert gas used to make bright city lights True or False

A boulder on top of a cliff has a potential energy of 12400J. How high above is the boulder?

If the graph represents speed what is measured on the x and y axes

It is difficult to lift a heavy stone than the lighter one on the earth, why?

The vapor pressure of ethanol at 25 degrees C is 7.83 kPa. Calculate the vapor pressure in atm. Round answer to 3 significant digits.