The thickness of oil spill can be measured by microwave reflection. A drone directs microwave beam from above. The two oil surfaces reflect microwave back to the drone. The refractive index is 1.5 for crude oil, and 1.34 for sea water. At one spot, the strongest reflected frequency (zeroth order interference) is 6 GHz. The oil thickness is mm.

According to newton’s law of universal gravitation, which statements are true? as we move to higher altitudes, the force of gravity on us decreases. as we move to higher altitudes, the force of gravity on us increases. as we gain mass, the force of gravity on us decreases. as we gain mass, the force of gravity on us increases. as we move faster, the force of gravity on us increases.

Blood pressure the total amount of blood the heart pumps in one minute 2. cardiac output the number of times your heart beats in a minute 3. dilate the amount of blood that the heart can pump in a single beat 4. heart rate the force exerted on the walls of the blood vessels by the blood that moves through them 5. stroke volume to widen or get larger in size

Is the number of complete movements of a wave per second.