Over time, the types of technology can vary and be improved upon so that more advanced techniques become more valued. This could be the situation with mining whereby back in the 1500's in underground mines the rock was broken by fire setting ie lighting a fire below the rock face to heat up the rock and then throwing cold water on it to crack it, so that it could be dug by hand. With the advent of explosives, this all changed so that the rock could be blasted. The increase in advance rates for an underground heading have thus gone from 5-20 feet per month to up to 300meters (984 ft) per month for a 24/7 mining operation, which is a huge improvement.
2- Metal
explanation
metal is the only conductor listed
In one of the startling coincidences sprinkled throughout
every field of math and science, the moment of maximum
height is popularly referred to as the "high" tide.
Answer:
ωf = 13 rad/s
Explanation:
- The angular acceleration, by definition, is just the rate of change of the angular velocity with respect to time, as follows:
- α = Δω/Δt = (ωf-ω₀) / (tfi-t₀)
- Choosing t₀ = 0, and rearranging terms, we have
where ω₀ = 5 rad/s, t = 4 s, α = 2 rad/s2
- Replacing these values in (1) and solving for ωf, we get:
- The wheel's angular velocity after 4s is 13 rad/s.
