Express your answers for the questions below in terms of the gravitational con- stant g, the masses, and the distance l. assume that the stars move on circular orbits. (a) what is the rotational period t of an equal-mass (m = m = m) double star of sepa- ration l? [10 points) (b) what is the rotational period t of an unequal-mass ( m m ) double star of separation l? (15 points) (c) what is the rotational period t of an equal-mass (m1 = m = m3 = m) triple star, where the stars are located at the corners of an equilateral triangle (side l)?

answer: a) y=-8x+5

a) m= -8

b) m= -2

c) m= 7

d) m= 6

find the surface area of the sphere to the nearest square unit. use a calculator.

a. 254 in.2

b. 64 in.2

c. 127 in.2

d. 1,018 in.2

the aurora is formed when charged particles emitted from the sun during a solar flare penetrate the earth's magnetic shield and collide with atoms and molecules in our atmosphere. these collisions result in countless little bursts of light, called photons, which make up the aurora.

auroras are generated by charged solar particles hitting molecules in earth's atmosphere. this usually happens in high latitudes, because our planet’s magnetic field tends to funnel these particles toward the poles. that’s why it can be experienced in northern ohio.