HELP ASAP If the half-life of a decaying isotope is 10 years, which statement is true after 8 years? A. There are more parent nuclei than daughter nuclei in a sample
B. The relative numbers of nuclei cannot be determined until 10 years have passed
C. The numbers of parent nuclei and daughter nuclei in a sample are equal
D. There are more daughter nuclei than parent nuclei in a sample

Next a skier is pulled by a tow rope up a frictionless ski slope that makes an angle of 15 with the horizontal. the rope moves parallel to the slope with a constant speed of 0.69 m/s. the force of the rope does 800 3 of work on the skier as the skier moves a distance of 8.4 m up the incline. (a) if the rope moved with a constant speed of 2.2 m/s how much work would the force of the rope do on the skier as the skler moved a distance of 8.4 m up the incline? at what rate is the force of the rope doing work on the skier when the rope moves with a speed of (b) 0.69 m/s and (c) 2.2 m/s?

Idon’t quite understand this problem

The difference between a red shift and a blue shift has to do with wavelength frequency. t or f