An athlete does one push-up period in the process, she moves half of her body weight, 250 n, a distance of 20 cm, this distance is the distance her gravity moves when she fully extend her arms how much work did you do after one push-up

The mass of a muon is 207 times the electron mass; the average lifetime of muons at rest is 2.21 μs. in a certain experiment, muons moving through a laboratory are measured to have an average lifetime of 7.04 μs. for the moving muons, what are (a) β (b) k, and (c) p? the rest energy of the electron is 0.511 mev.

With i really need the correct answer!

Given the position vector of the particle r(t)=(t+1)i+(t^2−1)j+2t k, find the particle's velocity and acceleration vectors at t=1