Answer:

Explanation:
We can use Newton's Universal Law of Gravitation to solve this problem:
., where
is acceleration due to gravity at the planet's surface,
is gravitational constant
,
is the mass of the planet, and
is the radius of the planet.
Since acceleration due to gravity is given as
, our radius should be meters. Therefore, convert
kilometers to meters:
.
Now plugging in our values, we get:
,
Solving for
:
.
Answer:
1.67 m/s
Explanation:
Momentum is conserved.
Initial momentum = final momentum
(30 kg) (10 m/s) + (35 kg) (-10 m/s) = (30 kg) v + (35 kg) (0 m/s)
300 - 350 = 30v
v = -5/3 m/s
Linus will move at 1.67 m/s in the direction opposite that he started.
The net force does not depend on the mass.
We have 12N to the right, and 19N to the left.
The net force is (19.0-12.0)N=7.0N to the left.