PLEASE HELP
From which frame of reference would a mountain be described as moving?*
A person climbing the mountain.

A bird flying near the mountain.

A person standing on the moon watching the earth rotate.

A photographer photographing the mountain from a street.

Two polarizers are oriented at 40∘ to each other and plane-polarized light is incident on them. if only 16 percent of the light gets through both of them, what was the initial polarization direction of the incident light?

Awater-filled u-tube manometer is used to measure the pressure inside a tank that contains air. the water level in the u-tube on the side that connects to the tank is 5 ft above the base of the tank. the water level in the other side of the u-tube (which is open to the atmosphere) is 2 ft above the base. determine the pressure within the tank.

What is the speed of an object at a given moment?