How did Thomson know atoms had an overall neutral charge?

He knew there were negative electrons but he came to the conclusion that the rest of the atom was positively charged, why was this? How did he know it would be positively charged?

A soda bottle is flexible enough that the volume of the bottle can change even without opening it. If you have an empty soda bottle (volume of 2.0 L) at room temperature (25 0C), what will the new volume be if you put it in your freezer (-4.0 0C) ?

A ferris wheel has a radius of 36 feet and completes one revolution every 5.4 minutes. what is the speed of the ferris wheel (in radians per minute) ?

A 82.1 kg person stands on a scale. what normal force does the scale exert on him? (Unit = N)

Describe the evolution of a pulsar over time, in particular how the rotation and pulse signal changes over time.

In a fusion reactor, the high temperature of the order of 108 k is required in order that what condition is met?

If a wave is traveling at a constant speed, and the frequency decreases, what would happen to the wavelength? A) It would increase B) It would decrease C) It would remain constant D) It would drop to zero

What conditions lead you to see an absorption line spectrum from a cloud of gas in interstellar space?

A car travels 35.0 mph north for 1.00 hour, then 40.0 mph east for 0.0500 hour, and finally 50.0 mph northeast for 2.00 hours. Calculate the average speed.

A 500 lb steel beam is lifted up by a crane to a height of 100 ft and is held there. A) How much work is being done to hold the beam in place? B) How much work was done to lift the beam?

If Light is shone through the slits of a card onto a sheet of white paper describe what is seen.