逸速く[ichihayaku] promptly
音速[onsoku] speed of sound
加速[kasoku] acceleration
加速運動[kasokuundou] accelerated motion
加速度[kasokudo] acceleration

快速[kaisoku] high speed
快速電車[kaisokudensha] high-speed train
角速度[kakusokudo] angular velocity
急速[kyuusoku] rapid (e.g. progress)
減速[gensoku] deceleration

高が[takaga] it's only ... (something)
意気軒高[ikikenkou] in high spirits
異常高温[ijoukouon] abnormally high temperatures
一斉高[isseidaka] all-round (market) advance
雲高[unkou] height of clouds

円高[endaka] high-valued yen
価値高い[kachitakai] valuable
可能性が高い[kanouseigatakai] very likely
勘定高い[kanjoudakai] calculating
気高い[kedakai] sublime