A writing desk stands on a base of external dimensions 80cm multiplied by 70cm and internal dimensions 70cm multiplied by 50cm. The total weight of the desk and base is 400N. Calculate the average pressure the desk exerts on a horizontal floor (i) in Ncm^-2 (ii) in Pa

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