Answers:
(a) 
(b) 397042.215 m
(c) 1917.76 m/s
Explanation:
The question is incomplete, please remember to write the whole question :) However, part (a) is written below:
(a) What is the escape speed on a spherical asteroid whose radius is 
and whose gravitational acceleration at the surface is 
Knowing this, let's begin:
a) In this part we need to find the escape speed 
on the asteroid:
(1)
Where:
is the universal gravitational constant
is the mass of the asteroid
is the radius of the asteroid
On the other hand we know the gravitational acceleration is , which is given by:
(2)
Isolating 
:
(3)
Substituting (3) in (1):
(4)
(5)
(6) This is the escape velocity
b) In this part we will use the Conservation of mechanical energy principle:
(7)
Being:
(8)
(9)
Where:
is the initial mechanical energy
is the final mechanical energy
is the initial kinetic energy
is the final kinetic energy
is the initial gravitational potential energy
is the final gravitational potential energy
is the mass of the object
is the radial speed of the object
is the distance above the surface of the object
Then:
(10)
Isolating :
(11)
(11)
(12) This is the distance above the asteroid's surface
c) We will use the Conservation of mechanical energy principle again, but now the condition is that the object is dropped at a distance 
. This means that at the begining the object only has gravitational potential energy and then it has kinetic energy and gravitational potential energy:
(13)
Isolating 
:
(14)
(15)
Finally:
