Explanation:
use the diagram^
horizontal velocity of the object nvr changes, it'll stay 50m/s till it hits the ground
initial vertical velocity = 0
to find the final vertical velocity, use the formula:

where u = 0m/s, a = 9.8m/s², and s = 2000m
solve for v.
for time taken to reach ground, use the formula:

where v = the value for v u calculated above, u = 0 m/s, a = 9.8m/s² and solve for t.
Answer:
a)Total distance = 399. 5 m
b)Total time =51.51 sec
c)Average speed = 7.75 m/s
Explanation:
For A to B:


v= u + at
8.33 = 0.42 x t
t=19.83 sec
1 Km/h=0.27 m/s
30 Km/h=8.33 m/s

s=82.6 m
For B to C
V= 8.33 m/s
s= V x t
s=8.33 x 30
s=249.9 m
For C to D

v= u - at
Final speed v=0
So
s=v x t/2
7= 8.33 x t/2
t=1.68 sec
Total distance = 82.6 + 249 .9 +7
Total distance = 399. 5 m
Total time = 19.83 + 30 + 1.68
Total time =51.51 sec
Average speed =Total distance/Total time
Average speed = 399.5/51.5
Average speed = 7.75 m/s
They are similar to the earth. Not relative to the outer planets