bai1: moi mot chiec kim khau giay co dg kinh = 0,005ml . Ap luc an vao kim la 10N ,Tinh ap suat mui kim tac dung len giay.
bai2: mot buc tuong dai 10m , day 22cm dc xay tren mot nen dat chiu dc ap suat toi da la 1000N/mvuong . tim chieu cao cua buc tuong . biet rang ti le rieng trung binh cua gach va vua la D=12500N/m^3