Question

A student reads the statement shown.

"The force of gravity exerted on an object decreases as the distance between the objects increases."

Using this statement, what inference can the student make regarding the movement of the planets around the Sun?

A. The orbital speeds of larger planets will be faster than smaller planets.

B. The orbital speeds of gaseous planets will be faster than rocky planets.

C. The orbital speeds of planets closer to the Sun will be faster than planets farther away.

D. The orbital speeds of planets with smoother surfaces will be faster than planets with rougher surfaces.​

Answer 1

Answer: C. The orbital speeds of planets closer to the Sun will be faster than planets farther away.

Explanation:

Centripetal force = gravitational force

$\tt m\dfrac{v^2}{r}=Fg$

$\tt Fg=G\dfrac{M.m}{r^2}$

Fg inversely proportional to distances (r)

$\tt v^2=\dfrac{Fg.r}{m}$

because the value of the gravitational force is getting smaller as the distance is getting further from the sun, the orbital speed of the planet will be getting smaller