The answers A, this is because Ice is originally water and when water goes below it's freezing point it turns into ice
The answer is "156.6 m/s".
This is how we calculate this;
-N + mg = ma = mv²/r
For "weightlessness" N = 0, so
0 = mg - mv²/r
g - v²/r = 0
v =√( gr)
g = 9.8 and r = 2.5km = 2500 m
v = √(9.8 x 2500)
= 156.6 m/s
The volume of the block of wood is given by length × width ×height
= 2.75 × 4.80 × 7.5
= 99 cm³
Density is given by mass/volume
Thus = 84.0 g/ 99 cm³
= 0.848 g/cm³
Hence; since the block is less dense than water (1 g/cm³) it will float
Answer:
a.
b.
c. 
Explanation:
Use Gravitational Force:

Use values given to have the results.
b.

Use m as the mass of the Moon. Using values of a. and m you have the answer.
c.

Use M mass of the planet. Use value of a and Mass of Planet.