Answer
given,
mass of ice hockey player = 110 Kg
initial speed of the skate = 3 m/s
final speed of the skate = 0 m/s
distance of the center of mass, m = 30 cm = 0.3 m
a) Change in kinetic energy



b) Average force must he exerted on the railing
using work energy theorem
W = Δ KE
F .d = -495
F x 0.3 = -495
F = -1650 N
the average force exerted on the railing is equal to 1650 N.
The compression curve would be theoretically given for a system of bodies in which the spring applies the force (Although in the same way the following process can be extrapolated to any system, depending on the type of Force to consider) For a spring mass system, the strength is given by Hooke's law as

Where,
K = Spring constant
x = Displacement
If we integrate based on distance we would have

This integral represents the area under the Force Curve based on each distance segment traveled.



This is the same formula that represents the elastic potential energy of a body. Therefore the correct answer is D.
Answer:
The expresion for the flux through the disk is:
Ф = E·πR^2·cos(Θ).
Explanation:
Let's sat the electric field has direction e and the normal to the disk has direction n (bold means vector quantities). So we have:
E=E·e (where E is the magnitud of the electric flied)
A=A·n
The flux for an uniform electric field and a flat surface is:
Ф=E×A
⇒ Ф = E·A·e×n = E·A·cos(angle(e,n)) = E·A·cos(Θ)
Since in this case the area is for a disk of radius R, 
So, Ф = E·πR^2·cos(Θ)
Answer:
oxygen silicon aluminun iron
Mass of the displaced material. In water it would be the mass of the water that the volume of the ball displaces.