There are several information's of immense importance already given in the question. Based on the given information's the answer to the question can easily be determined.
Distance covered by the bicycle = 5000 meter
Time taken by the bicycle to reach the distance = 500 second.
Velocity of the bicycle = Distance / Time taken
                                   = 5000/500 meter/second
                                   = 50 meter/second
So the velocity of the bicycle is 50 meter per second. I hope the procedure is clear enough for you to understand. In future you can always use this procedure for solving similar problems.
        
             
        
        
        
Formula to find gravitational potential energy:
mgh
m: mass
g: gravitational acceleration
h: height (relative to reference level)
so the P.E. at 1.0.m is (5x9.8x1)= 49J
P.E. at 1.5m is (5x9.8x1.5) =73.5J
P.E. at 2.0m is (5x9.8x2)=98J
        
             
        
        
        
Answer
Given,
Time period of star,T = 3.37 x 10⁷ s
Radius of circular orbit,R = 1.04 x 10¹¹ m
a) Angular speed of the planet
     
 
    
b) tangential speed
    
        v = 1.94 x 10⁴ m/s
c) centripetal acceleration magnitude
       
           a = 3.62 x 10⁻³ m/s²
 
 
        
             
        
        
        
It would b 6 days and 6 hours 
You would times 16 by 8 which gives 128km a day. To find how many days you would divide 800 by how many kilometres they cover a day which is 128
So 800/128 =6.25 which converts to 6 days and 6 hours.