Answer:
C. -12 ab
Explanation:
The restoring force on a spring is given by Hooke's law:

where
k is the spring constant
x is the stretched (or compressed) displacement of the spring
In this problem we have:
k = 4a
x = 3b
Substituting into the equation, we find:

And the negative sign means that the direction of the force (negative) is opposite to the direction of the displacement (positive).
If the mass of the object and the volume of the object is determined;
Then, the density of the object is determined by taking the ratio of the mass and volume.
<h3>What is density of an object?</h3>
The density of an object is the ratio of the mass and volume of that object.
Mathematically;
To determine the density of an object therefore, the physical characteristics of mass and the volume of the object are measured.
The mass of the object is obtained using a scale or a balance.
The volume of the object if a solid is obtained using a displacement bottle. If it is a liquid, a measuring cylinder is used.
The density of the object is then obtained by taking the ratio of the mass and the volume of the object.
In conclusion, the density of an object is determined from the volume and mass ratio.
Learn more about density at: brainly.com/question/1354972
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Answer:

Explanation:
Given data
Mass m=67.0 kg
Final Speed vf=8.00 m/s
Initial Speed vi=2.00 m/s
Distance d=25.0 m
Force F=30.0 N
From work-energy theorem we know that the work done equals the change in kinetic energy
W=ΔK=Kf-Ki=1/2mvf²-1/2mvi²
And

So

and we know that the force the sprinter exerted Fsprinter the force of the headwind Fwind=30.0N
So
Vapor is usually made with water and it would be made with gas.
Answer:
gravity
Explanation:
That would make the most sense from what I know