Which one of the statements below is true about mechanical waves? They must travel in empty space.
They can travel in a vacuum.
Both sound and light are examples of mechanical waves.
They require a medium to travel through.

Most energy in an ecosystem comes originally from_

Isla’s change in velocity is 30 m/s, and hazel has the same change in velocity. which best explains why they would have different accelerations? isla had negative acceleration, and hazel had positive. isla had a different time than hazel. isla had positive acceleration, and hazel had negative. isla went a farther distance than hazel.

Unpolarized light of intensity so passes through two sheets of polarizing material whose transmission axes make an angle of 60∘ with each other as shown in the figure. what is the intensity of the transmitted beam, st?