An astronaut leaves the International Space Station (ISS) on a tethered line. Although ISS and Earth exert gravitational force on the astronaut, why does she appear to be weightless.

A) Earth only exerts gravitational force on objects at its surface.
B)The mass of the astronaut is insufficient to be affected by gravity.
C) Earth and ISS cancel each other's gravitational force on the astronaut.
D)The distance from Earth and mass of ISS exert negligible gravitational force on the astronaut.

Look at the spectrums of a star moving towards earth and a motionless star. which of these is a correct inference that can be draw from the observation of the two spectrums? (2 points) the spectrum of a motionless star is difficult to be viewed separately using oridinary telescopes. the spectrum of a motionless star is identical to the spectrum of a star which moves towards earth. the spectrum of a star shifts towards the red region when the star moves towards earth. the spectrum of a star shifts towards the blue region when the star moves towards earth.

Acontrol during an experiment. might change remains constant does not exist does change

How many protons, electrons, and neutrons are in each of the following isotopes? a. zirconium-90 b. palladium-108 c. bromine-81 d. antimony-123