To find a general equilibrium point for a spring based on the hook law, it is possible to start from the following premise:
Hook's law is given by:

Where,
k= Spring Constant
Change in Length
F = Force
When there is a Mass we have two force acting at the System:
W= mg
Where W is the force product of the weigth. Then the force net can be defined as,

But we have a system in equilibrium, so

We find the equilibrium for any location when

Answer:
Force = 35 N
Explanation:
From Newton's third law of motion, the boy must apply a force greater than the weight of the sled to lift it.
weight of sled = mg
where m is its mass and g the force of gravity on it.
weight of sled = 50 N
Force applied by the boy on the sled = 15 N
Since the force applied on the sled by the boy is lesser than the weight of the sled, then;
Force that the sled exerts on the student = 50 - 15
= 35 N
The force exerted by the sled on the student is 35 N.
The first answer in the blank is pours out of you, the second answer in the space provided is diffuse. It is because a person who has an effusive personality will likely pour out his or her emotions while the motor oil will likely diffuse if this has been spilled out of the can.