Machines makes work easier by increasing the amount of force that is applied, and changing the direction in which the force is applied !! Hope it helped (p.s. I had this same question)
Answer:

Explanation:
Given data:



Let the distance traveled by the object in the second case be 
In the given problem, work done by the forces are same in both the cases.
Thus,





Answer:
V2 = 1.33m/s
Explanation:
M1 = 30 ton
M2 = 90 ton
V1 = 4 m/s
V2 = ?
Assumption: momentum conserved, no friction
initial momentum = final momentum = 0
momentum : p = MV
(M1*V1) - (M2*V2) = 0
V2 = (30*4)/90 = 1.33m/s