Ancient civilizations had a high demand for raw materials, like clay, diverse rocks and, most of all, metals. These were required for buildings, crafts, agriculture, their armed forces, financial concerns, art and culture. Clays and rocks produced by opencast mining primarily served for the production of bricks and building blocks, which were used for civil and hydraulic engineering.
Answer:
Explanation:
The trick is in finding the volume.
Final Volume = 26.64
Initial Volume=<u>20.92</u> Subtract
Metal Volume 5.72 cm^3
Density = mass / volume
Density = 72.17 / 5.72
Density = 12.617
The answer is <span>Guardrails and protective equipment. </span><span>When hoisting a personnel platform, guardrails and protective equipment need not be engaged when they occupied platform is in a stationary position. </span>
Answer:
Explanation:
Using conservation law of momentum
let m₁ = mass of the railroad, initial u₁ = 3.49 m/s
let m₂ = mass of one of the coupled car, u₂= 1.28m/s
let m₃ = mass of the second car u₃ = 1.28 m/s
m₁u₁ + m₂u₂ + m₃u₃ = v ( m₁ + m₂ + m₃)
since the masses are the same
m₁ = m₂ = m₃
m ( 3.49 + 1.28 + 1.28) = 3m v
6.05 m = 3 mv
v = 6.05 m / 3m = 2.0167 m/s
b) kinetic energy lost = energy before collision - energy after collision
= (0.5m₁u₁² + 0.5 ( m₁+m₂) u₂² - 0.5 ( m₁ + m₂ + m₃) v
= (6.58365 + 1.7712) - 6.5951 = 1.76J
Answer:
220.7
Explanation:
distance traveled is 1.5*5=7.5m
PE gain is MGH=3*9.81*7.5=220.7