Answer:
charged pith ball works well to show the Coulomb force between two charged objects. If a glass rod is rubbed with silk, the silk rubs some electrons off the rod. The rod thus becomes positively charged. ... Since like charges repel, the pith balls repel one another.
Explanation:
Adding both distances together, you get a total of 1800 miles. With the total travel time of 4 hours, you divide the distance traveled by the time it took. so 1800/4=450 mph
Answer:
and 
, second order does not exist
Explanation:
n = Number of lines grating = 
= Wavelength
m = Order
Distance between slits is given by


m = 1
We have the relation

m = 2

The first and second order angles for light of wavelength 400 nm are
and
.

m = 1

m = 2

Here
so there is no second order angle for this case.
The first order angle for light of wavelength 700 nm are
.
Second order angle does not exist.