Answer:
6.51 g/c.c
Explanation:
mass, m = 114 g
initial volume, V1 = 25 mL
final volume, V2 = 42.5 mL
Volume of the metal piece, V = V2 - V1 = 42.5 - 25 = 17.5 mL
1 mL = 1 c.c
So, Volume of metal, V = 17.5 c.c.
Let the density of the metal is d.
density = mass / volume
d = 114 / 17.5 = 6.51 g/c.c
Thus, the density of metal is 6.51 g/c.c.
D = 318 meters
vi = 0 m/s
vf =????
a = 9.81
Formula
=======
vf^2 = vi^2 + 2*a*d
Substitute and solve.
================
vf^2 = 0^2 + 2 * 9.81 * 318
vf^2 = 6239.16
v = sqrt(6239.16)
v = 78.990 m/s I guess down is minus in your classroom.
Anyway pick -79 <<<<<=======
Answer:

Explanation:
Notation
represent the tensile strength for the Kevlar 49 fibers
represent the tensile strength for the epoxy resin
79% by volume is made of Kevlar 49 fibers
The rest 100-79=21% is made of epoxy resin
Tensile strength is a "measurement of the force required to pull something such as rope, wire, or a structural beam to the point where it breaks". Can be defined as "the maximum amount of tensile stress that it can take before failure".
For this case we need to use a basis of calculus since we don't know the total volume but we can assume a reference value on order to make the calculations.
If we assume a total volume of
we can do the follwoing balance:

We can replace the values given:


So then the strength of the composite material is : 
<h2>
Answer:Option F</h2>
Explanation:
Metals have few number of electrons in their valence shell.
The force with which the nucleus of the metal atom is pulling the electron towards itself is lower on the valence shell because the distance between the nucleus an valence shell is large.
So,there are a lot of free electrons in metals.
When the ends of metals are at different potential,electrons flow from one end to another to balance the potential.This feature of metals allows them to conduct electricity.
Similarly,when the ends of metals are at different temperatures,conduction will take place and electrons are the carriers of conduction.This feature of metals allows them to conduct heat.
So,metals are good conductors of heat and electricity.