The answer should be copper. hope this helps :D
Answer:

Explanation:
given,
length of the ship = 120 m
length of model of the ship = 4 m
Speed at which the ship travels = 70 km/h
speed of model = ?
by using froude's law

for dynamic similarities




hence, the velocity of model will be 12.78 km/h
Answer:
F = M a
W = M g equivalent equation to express weight of object of mass M
M = W / g = 2867 N / 9.8 m/s^2 = 292.6 kg
Calculate velocity at halfway to the ground.
vfinal = root 2ad
v = root (2*9.81m/s^2*25)
v = 69.367175234 m/s
Kinetic energy = 1/2mv^2
Kinetic energy = 1/2 * (69.367175234 m/s^s^2
Ek = 2405.9025 Joules
Answer:
Option D 3.9
Explanation:
First, you need to use the correct equation which is the following:
COP = Q/W
Where:
Q = heat absorbed
W = work done by the pump
COP = coefficient of perfomance
We have all the data, so, all you need to do is replace in the above expression and you shoould get the correct result:
COP = 30 / 7.7
COP = 3.896
This result you can round it to 3.9. option D.