Which evidence has led scientists to conclude that there are different layers within earths interior

Awind turbine is initially spinning at a constant angular speed. as the wind's strength gradually increases, the turbine experiences a constant angular acceleration 0.173 rad/s2. after making 2870 revolutions, its angular speed is 132 rad/s. (a) what is the initial angular velocity of the turbine? (b) how much time elapses while the turbine is speeding up?

When the magnetic domains in a material can be aligned, but eventually drift out of alignment, the material is

Explain why electric current cannot exist if a current doesn't have a voltage source.