What is the half-life of a radioisotope? half of the time needed for a sample of radioisotope to become stable
the time needed for half of a sample of radioisotope to decay
the time needed before the first half of a radioisotope begins to decay
half of the time needed for a radioisotope to leave the body

An astronaut floating in space is trying to use her jetpack to get back to her space station, but she is being pulled away by a nearby planet, as shown in the image below. her jetpack provides a constant thrust of 310 n. if she angles her jetpack in such a way that it cancels out the vertical force due to the planet's gravity, what is her net horizontal force? thaud 487 o a. 54.8 n toward the space station o b. 212.9 n toward the space station o c. 185.2 n toward the space station o d 956 n toward the space station