Step-by-step explanation:
The given data is as follows.
 Height, h = 40 m, F = 160 N
 Time, t = 10 sec, Work, w = ?
Calculate the work by using the formula as follows.
 Work = Force × displacement
 = 160 N × 40 m
 = 6400 J
Now, calculate the average speed as follows.
 Potential energy = Kinetic energy
 m × g × h = 

Cancelling mass, m from both the sides the relation will become: 
 g × h = 

 or, v = 

 = 

 = 
 m/s
 m/s
 = 28 m/s
Thus, we can conclude that work done is 6400 J and average speed is 28 m/s.