Ko te kaupapa mahi o te parai e ahu mai ana i te waku, mā te whakamahi i ngā papa parai me te kōpae parai (pahu) me ngā potae me te waku whenua, ka hurihia te kaha nekeneke o te waka hei kaha wera i muri i te waku, ka mutu te waka. Me whakarato e te pūnaha parai pai, whai hua hoki te kaha parai pumau, rawaka, me te taea te whakahaere, ā, me whai kaha tuku waipēhi me te tohatoha wera pai kia taea ai te tuku tika me te whai hua o te kaha e tukuna ana e te taraiwa mai i te pēra parai ki te papu matua me ngā papu-iti, me te karo i te pakaru waipēhi me te pirau parai i puta mai i te wera nui. He parai kōpae me he parai pahu, engari hei tāpiri atu ki te painga utu, he iti ake te whai hua o ngā parai pahu i ngā parai kōpae.
te waku
Ko te "waku" e pā ana ki te ātete o te nekehanga i waenga i ngā mata pa o ngā mea e rua i roto i te nekehanga whanaunga. Ko te rahi o te kaha waku (F) he rite ki te hua o te tauwehenga waku (μ) me te pēhanga poutū pai (N) i runga i te mata o te kaha waku, e whakaatuhia ana e te tātai ā-tinana: F=μN. Mō te pūnaha parai: (μ) e pā ana ki te tauwehenga waku i waenga i te papa parai me te kōpae parai, ā, ko N te Kaha Pahi e tukuna ana e te piston caliper parai ki runga i te papa parai. Ko te nui ake o te tauwehenga waku i puta mai i te nui ake o te waku, engari ka rerekē te tauwehenga waku i waenga i te papa parai me te kōpae nā te wera nui i puta mai i te waku, arā, ka rerekē te tauwehenga waku (μ) me te pāmahana, ia momo papa parai nā te rerekētanga o ngā rauemi me te rerekētanga o te pihi tauwehenga waku, nō reira ka rerekē te pāmahana mahi pai o ngā papa parai rerekē, ā, ko te awhe pāmahana mahi e tika ana, me mōhio te katoa i te wā e hoko ana i ngā papa parai.
Te whakawhiti i te kaha aukati
Ko te kaha e tukuna ana e te piston caliper parai ki te papa parai ka kiia ko te Kaha Pedal. Whai muri i te whakanui ake i te kaha o te taraiwa e takahi ana i te pedal parai e te rīwhi o te tikanga pedal, ka whakanuia te kaha e te whakanui mana korehau mā te whakamahi i te kaupapa o te rerekētanga pēhanga korehau hei pana i te papu matua parai. Ko te pēhanga wai e tukuna ana e te papu matua parai ka whakamahi i te pānga tuku mana korehau kore e taea te pēhi, ka tukuna ki ia papu-iti mā roto i te ngongo parai, ā, ka whakamahia te "kaupapa PASCAL" hei whakanui ake i te pēhanga me te pana i te piston o te papu-iti hei pana i te kaha ki te papa parai. E pā ana te Ture a Pascal ki te meka he rite tonu te pēhanga wai i ngā wāhi katoa i roto i te ipu kati.
Ka whiwhihia te pēhanga mā te wehewehe i te kaha e pā ana ki te rohe taumaha. Ina ōrite te pēhanga, ka taea e tātou te whakatutuki i te pānga o te whakanui mana mā te whakarerekē i te ōwehenga o te rohe taumaha me te rohe taumaha (P1=F1/A1=F2/A2=P2). Mō ngā pūnaha aukati, ko te ōwehenga o te papu katoa ki te pēhanga papu-iti ko te ōwehenga o te horahanga piston o te papu katoa ki te horahanga piston o te papu-iti.
