Answer:
W = 343.2 J
Explanation:
Given that,
Mass of bale of hay = 26 kg
Horizontal force exerted = 88 N
Distance moved, d = 3.9 m
Work done, W = Fd
Put all the values,
W = 88 N × 3.9 m
= 343.2 J
So, the work done is 343.2 J.
To solve this problem it is necessary to apply the concepts related to Hooke's Law as well as Newton's second law.
By definition we know that Newton's second law is defined as

m = mass
a = Acceleration
By Hooke's law force is described as

Here,
k = Gravitational constant
x = Displacement
To develop this problem it is necessary to consider the two cases that give us concerning the elongation of the body.
The force to keep in balance must be preserved, so the force by the weight stipulated in Newton's second law and the force by Hooke's elongation are equal, so

So for state 1 we have that with 0.2kg there is an elongation of 9.5cm


For state 2 we have that with 1Kg there is an elongation of 12cm


We have two equations with two unknowns therefore solving for both,


In this way converting the units,


Therefore the spring constant is 313.6N/m
A graph of real speed can have a section that's as steep as you want,
but it can never be a perfectly vertical section.
Any vertical line on a graph, even it it's only a tiny tiny section, means
that at that moment in time, the speed had many different values.
It also means that the speed took no time to change from one value to
another, and THAT would mean infinite acceleration.