Which statement is true about the motion of a planet in its orbit around the sun?

Question

A) the orbital speed increases as the planet approaches apogee

B) the planets orbital speed changes as it moves closer and farther from the sun

C) perigee is when the orbital speed is at its least

D) the orbital speed of the planet remains constant as it orbits the sun

I put b. Can someone tell me if I’m right or not pls

Answer 1

If a planet existed that had a period twice that of earth, what would be the length of the semi-major axis as it orbits the sun

A) 2.83 AU
B) 2 AU
C) 1.59 AU
D) 4 AU

I put 2.83 AU
Can someone tell me if this is right too pls?

Answer 2

I also need help with this one, but I have no idea what the answer is. Can someone pls help me

If a planet had a semi-major axis length of 2.3 AU as it orbits the sun, what would be its period in years?

A) 12.2 years
B) 1.74 years
C) 2.3 years
D) 3.49 years

Answer 3

Never mind the answer is
D) 3.49 years

Cuz when you do
T^2=s^3
S=2.3
T^2= (2.3)^3
T^2 = square root of 12.167
T^2 = 3.488

Answer 4

I submitted it. I got everything right except the 2nd question. It was actually 1.59 AU

Answer 5

T = constant * R sqrtR
say T = R^1.5 since only ratios important
if R = 10
it T= 10
R^1.5 = 10
1.5 log R = 1
logR = 1/1.5
R = 4.64
if R = 20
logR = 1.3/1.5
R = 7.35
7.35 / 4.64 = 1.584

Answer 6

1. D. Elliptical
2. C. The sun is located at one focus.
3. C. The planet's orbital speed changes as it moves closer and farther from the Sun.
4. A. 1.59 AU
5. C. 3.49 Years

Hope this helps