Question

A moon of mass 1×10^20kg is in a circular orbit around a planet. The planet exerts a gravitational force of 2×10^21n on the moon. The centripetal acceleration of the moon is most nearly:.

Answer 1

Hi there!

In this instance, the centripetal force experienced by the moon is equivalent to the gravitational force.

Thus:
$\large\boxed{F_c = F_g}$

Centripetal acceleration, according to Newton's Second Law:

$\Sigma F = ma \\\\F_c = m * a_c\\\\a_c = \frac{F_c}{m}$

Therefore:

$a_c = \frac{F_g}{m_m} = \frac{2 * 10^{21}N}{1 * 10^{20}kg} = \boxed{20 N/kg}$