Math skills 5: working with units & other sections for ch2
The Moon's angular size is about 1/2∘. What is this in arcminutes?
30 arcminutes (30') [(1/2)degree] (60'/degree) = 30' note that " *'* " means arcminute after a number
How many arcseconds are in a full circle?
360 degree x 60 min/degree x 60 sec./min. = 1,296,000
a week after full moon. the moon's phase is
3rd quarter
4 boxes * 5 (kg/box) means
4 boxes of 5 kg per box
part f A large boulder has a volume of 1000 cubic meters and a mass of 3,200,000 kilograms. What is the density of the boulder, in grams per cubic centimeter? A large boulder has a volume of 1000 cubic meters and a mass of 3,200,000 kilograms. What is the density of the boulder, in grams per cubic centimeter?
D= m / v = [ (3.2 X 10^6 kg) / (10^3m^3) ] X (10^3g / 1 kg) X (1m / 10^2 cm)^3 = 3.2 g / cm^3
There are 360∘ in a full circle. How many arcminutes are in a full circle?
There are 60 arcminutes in one degree there are 360 degrees in a circle there fore one full rotation is equal to (360 * 60=21600 arcminutes) *21600 arcminutes*
part c Recall that 1 foot = 12 inches. Therefore, 1 square foot = __144in^2___ square inches.
because 1ft^2 = (12)^2in^2 --> 144in^2 note: both the 12 and the inches unit needed to be squared which is why it was made into 144 in^2
when we see Saturn going through a period of apparent retrograde motion, it means
earth is passing Saturn in its orbit, with both planets on the same side of the Sun.
if the sun rises precisely due east
it must be the day of either the spring or fall equinox
kg/(m^3) means
kilograms per cubic meter
problem 2.27 2 stars that are in the same constellation
may actually be very far away from each other
m^3
meters cubed (cubic meters)
in words, M/S means
meters per second
M/S^2 means
meters per second squared
m^2 means
meters squared (actual answered.. square meters)
In winter, Earth's axis points toward the star Polaris. In spring ------------------------------------------------ the axis also points toward Polaris
problem 2.27
part b --> 2 years X *12 months/ 1yr* = 25 months --> 24 months X *1 year/12 months* = 2 years --> 6 m (meters) X *100 cm/ 1 m* = 600 cm (centimeters) --> 600 cm X *1 m / 100 cm* = 6 m
the answer looks like this -->*text*
if there is going to be a total lunar eclipse tonight, then you know that:
the moon's phase is full
the fact that we see the same face of the moon tells us that
the moon's rotational period is the same as its orbital period
Beijing and Philadelphia have about the same latitude but very different longitudes. therefore, tonight's night sky in these two places
will look about the same
when it is summer in Australia, the season in the US is
winter
the north celestial pole is 35(degrees) above your northern horizon. this tells you that
you are at latitude 35 N
What is the Moon's angular size in arcseconds?
1800'' note " *''* " means arcseconds
1.58deg
1deg 34' 48''
24.7degree
24deg 42' 0''
part e The surface area of a small moon is 50,000 square kilometers, which is equivalent to __50,000 X 1000^2___ square meters. (Recall that 1 kilometer = 1000 meters.)
(1000m / 1km)^2 = [ (1000^2*m^2) / 1 km^2 ]
0.1deg
0 , 6', 0''
0.001
0, 0' , 3.6''
0.01 deg
0,0',36''
part d Recall that 1 centimeter = 10 millimeters. Therefore, 1 cubic centimeter = __1000___ cubic millimeters
1 cm3=(10 mm)3=103 mm3=1000 mm3 Note: follows part c
