Aset of keys slides along the floor, coming to rest 1.4 meters from where it started. if the initial speed of the keys was 2.1m/s , then the acceleration of the keys is ?

Newtons view of arrangement of the universe. don't copy from anywhere.

What is the frequency if a wave that pases a given pount 22 times in 2 seconds

Auniform electric field exists in the region between two oppositely charged plane parallel plates separated by a distance of 1.60 cm . a proton is released from rest at the surface of the positively charged plate and strikes the surface of the opposite plate in a time interval of 3.20×10-6 s. 1-find the magnitude of the electric field. use 1.60×10-19c for the magnitude of the charge on an electron and 1.67×10-27kg for the mass of a proton 2-find the speed of the proton when it strikes the negatively charged plate